How to View a Solar Eclipse Without Damaging Your Eyes

How to View a Solar Eclipse Without Damaging Your Eyes:

The total solar eclipse of 2016 taken from a NASA webcast on March 8, 2016. The image was taken from Woleai Island in Micronesia. The next total solar eclipse will cross the entire continental U.S. on Aug. 21, 2017.

Credit: NASA TV

Editor's note: This story was originally posted on Feb. 2 and was updated on Aug. 19 with new resource links for eye safety during the 2017 total solar eclipse. 

We're just days away from the total solar eclipse of Aug. 21 and it's a good time for a refresher course on how to safely observe the event. Your parents probably told you to NEVER look directly at the sun with your naked eye. In fact, you've probably been told that by lots of reputable sources (including our own Space.com). But according to NASA and four other science and medical organizations, it's OK to look at a total solar eclipse with the naked eye — but only when the face of the sun is totally obscured by the moon.

A total solar eclipse happens when the central disk of the sun is completely covered by the moon. Many people have probably seen a partial solar eclipse, in which the disk of the moon appears to take a bite out of the sun's disk, but never fully obscures it. But total solar eclipses are a much rarer sight. And on Monday, a total solar eclipse will cross the continental U.S. from coast to coast.

A joint statement from NASA and the four other organizations says that with the right information, skywatchers can safely view the total solar eclipse in its full glory with the naked eye.

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Anyone in the United States on Aug. 21, 2017, will be able to see at least a partial solar eclipse (weather permitting, of course). But only those people in what's known as the "path of totality" will see a total solar eclipse. For the Aug. 21 eclipse, the path of totality is about 70 miles wide (112 kilometers), and extends from Oregon to South Carolina. Depending on where observers are located, the sun may be completely obscured by the moon for up to 2 minutes and 40 seconds.

The path of the total solar eclipse of 2017. Locations within the path of totality will experience up to 2 minutes and 40 seconds of darkness.

Credit: NASA


"During those brief moments when the moon completely blocks the sun's bright face … day will turn into night, making visible the otherwise hidden solar corona (the sun's outer atmosphere)," according to NASA's Eclipse website. "Bright stars and planets will become visible as well. This is truly one of nature's most awesome sights."

But in order to see this awesome natural sight, skywatchers need to know how to view the eclipse safely. In an effort to inform the public on this topic, an information guide on safe viewing has been written up and released by NASA, along with the American Astronomical Society (AAS), the American Academy of Ophthalmology, the American Academy of Optometry and the National Science Foundation.

Eye protection for looking at the sun

Looking directly at the sun without eye protection can cause serious eye damage or blindness. But there are ways to safely observe the sun. During a partial solar eclipse, people often use pinhole cameras to watch the progress of the moon across the sun's surface (pinhole cameras are easy to make at home). This is an "indirect" way of observing the sun, because the viewer sees only a projection of the sun and the moon.

To view the sun directly (and safely), use "solar-viewing glasses" or "eclipse glasses" or "personal solar filters" (these are all names for the same thing), according to the safety recommendations from NASA. The "lenses" of solar-viewing glasses are made from special-purpose solar filters that are hundreds of thousands of times darker than regular sunglasses, according to Rick Fienberg, press officer for the American Astronomical Society (AAS). These glasses are so dark that the face of the sun should be the only thing visible through them, Fienberg said. Solar-viewing glasses can be used to view a solar eclipse, or to look for sunspots on the sun's surface.

But beware! NASA and the AAS recommend that solar-viewing or eclipse glasses meet the current international standard: ISO 12312-2. Some older solar-viewing glasses may meet previous standards for eye protection, but not the new international standard, Fienberg said.

"Manufacturers that meet this standard include Rainbow Symphony, American Paper Optics and Thousand Oaks Optical," according to the information sheet on safe eclipse viewing. (Click any of the company links to find out how to purchase eclipse glasses). "Homemade filters or ordinary sunglasses, even very dark ones, are not safe for looking at the sun."

Fienberg said some manufacturers are making solar-viewing glasses with plastic frames, rather than the traditional paper frames. While these may look like regular sunglasses, do not be mistaken. Sunglasses are never a substitute for solar-viewing glasses. Fienberg said some people may even try to view the sun through two or three pairs of sunglasses in an attempt to replicate the protective power of real solar-viewing glasses; however, even multiple pairs of sunglasses will not protect your eyes from sun damage.

Telescopes, cameras, binoculars and other optical devices need their own solar filters. Solar-viewing glasses are not a substitute for a proper solar filter on magnification devices. Never view the disk of the sun through a telescope, binoculars or camera without a proper solar filter. Solar-viewing glasses are not powerful enough to protect your eyes from magnified sunlight. Even if you are wearing solar-viewing glasses, viewing the disk of the sun through a magnification device will result in serious eye damage if the device is not equipped with a proper solar filter, according to the viewing safety sheet.

"The concentrated solar rays will damage the filter and enter your eye(s), causing serious injury," according to the safety recommendations. "Seek expert advice from an astronomer before using a solar filter with a camera, a telescope, binoculars, or any other optical device."

Fienberg said there is no need for skywatchers to use a telescope during the eclipse, but a pair of binoculars can be helpful during totality. But, as per the recommendations, do not attempt to look at the disk of the sun through binoculars, even with solar-viewing glasses.

The safety sheet offers these tips regarding solar filters/eclipse glasses/solar viewers:

• Always inspect your solar filter before use; if scratched or damaged, discard it. Read and follow any instructions printed on or packaged with the filter. Always supervise children using solar filters. 
• Stand still and cover your eyes with your eclipse glasses or solar viewer before looking up at the bright sun. After glancing at the sun, turn away and remove your filter — do not remove it while looking at the sun. 
• Do not look at the uneclipsed or partially eclipsed sun through an unfiltered camera, telescope, binoculars or other optical device.

Safety during totality

Now that you have some general information about how to view the sun safely, here are NASA and the AAS's recommendations for how to safely view the total solar eclipse with the naked eye. Again, these tips come from NASA's safety information sheet here.

Viewers who are looking at the eclipse with solar-viewing glasses will be able to see when the sun's face is completely obscured by the moon (because, once again, the only light that can penetrate these solar-viewing glasses is the light from the sun's disk). Viewers will be able to observe the moon creep slowly over the sun's disk and eventually cover the sun entirely.

In the moments before totality, viewers looking through their solar-viewing glasses will see a crescent of light from the sun growing thinner and thinner as the moon progresses over its face. In the last few seconds just before the disk of the sun is entirely covered by the moon, the crescent will break up into a series of small dots of light that look like beads on a string (typically there are about three to eight such dots, according to Fienberg). These are called Baily's beads (after Francis Baily, the British astronomer who discovered them). Once the last bead disappears, the face of the sun has been covered by the moon, and totality has begun. [Solar Eclipses: An Observer's Guide (Infographic)]

"If you are within the path of totality, remove your solar filter only when the moon completely covers the sun's bright face," according to the official safety information sheet.

This image from NASA shows that the only time it is safe to remove your eye protection during a total solar eclipse is when the disk of the sun is entirely covered by the moon.

Credit: NASA


The safety information sheet also recommends that viewers be aware of another drastic change that takes place during a total solar eclipse: light levels drop dramatically, as if the world has suddenly been plunged into dusk. This is one indicator that totality has begun, and it is safe to take off your eclipse glasses.

When should you put your glasses back on? The official recommendations from the agencies suggest that viewers put their solar-viewing glasses back on before any part of the sun's disk becomes visible again.

"Experience totality, then, as soon as the bright sun begins to reappear, replace your solar viewer to glance at the remaining partial phases," the information sheet said.

In order to anticipate when the disk of the sun will reappear, viewers should first be aware of about how long the total eclipse should last where they are standing — the total eclipse will last, at most, about 2 minutes and 40 seconds. The nearer that viewers are to the edge of the path of totality, the shorter the total eclipse will be. Viewers who want to observe the total solar eclipse with the naked eye should try to move closer to the center of the path, so there is ample time to observe the eclipse safely.

Fienberg said that viewers should be aware of the moon moving across the surface of the sun during totality. The side of the sun that was the last to disappear behind the moon will be opposite to the side that is first to reappear. On the side of the moon where the sun will reappear first, viewers should look out for the "reddish hue" of the chromosphere, the layer of the sun's atmosphere that is closest to its surface. The sun will begin to reappear just as it disappeared — first as dots of light. If a dot of sunlight appears on the edge of the moon, it means totality is complete.

Baily's beads and diamond rings

The AAS and NASA are expecting huge crowds to flock to the path of totality for the 2017 total solar eclipse, including more experienced eclipse watchers. These seasoned observers may start shouting "Baily's beads!" when the spots of light appear at the edge of the moon. As the eclipse nears totality, people may also shout "Diamond ring!" Fienberg explains that when only one "bead" is still visible at the edge of the moon just before totality, it will glow like a diamond, and the red corona of the sun will create a circular band of light. Together, they will look like a diamond ring.

Experienced observers may decide to look at the eclipse with the naked eye just before the sun is completely covered by the moon, when the diamond ring appears.

"If you're in a group you'll hear people start screaming 'Diamond ring! Diamond ring! Filters off!'" Fienberg said. "If you're paying strict attention to the recommendation that you should not look at the sun without a filter, when any part of the bright face is still visible, you'll wonder if all those people are going blind, but they're not. The reason they're not is because it only lasts a second or so, and then it's gone and you see the corona, and its dark and its spectacular and beautiful."

While you may see some people removing their solar-viewing glasses before the eclipse reaches totality, this is not recommended by the official eclipse-viewing guide from NASA and the AAS.

What you'll see during a total solar eclipse

While Fienberg is adamant about eclipse-viewing safety, he is equally insistent that skywatchers should view the total solar eclipse with the naked eye, because the experience is like nothing else on Earth.

The sun's atmosphere "is always there but we can't see it," Fienberg said. "Satellites in orbit that block out the bright disk of the sun can see it, but from ground, we don't see it except during totality. And it is just magnificently beautiful. It's awesome in the truest sense of the word. It just makes your jaw drop. The first time you see it you just can't believe how beautiful it is. And it brings tears to people's eyes."

This composite image captures close to what the human eye sees during a total solar eclipse. The ribbons of light are the sun's atmosphere, which is controlled by the magnetic field.

Credit: NASA/S. Habbal, M. Druckmüller and P. Aniol


The sun's atmosphere isn't a uniform haze like the Earth's atmosphere, Fienberg said. It's "a tangle of streamers and jets and loops and twists and all kinds of stuff because its controlled entirely by the sun's magnetic field, which is very tangled and twisted."

The chromosphere, the atmosphere closest to the sun's surface, "is an unbelievably beautiful, pure magenta-red color. If the chromosphere is active and there are eruptions going on on the edge of the sun, you'll see prominences — they look like flames or jets of this really beautiful hot-pink magenta gas that are extending out beyond the silhouette of the moon," he said.

None of these features will be visible to viewers wearing eclipse glasses.

Fienberg is an eclipse chaser; he has traveled all over the world to see total solar eclipses. On his very first eclipse-viewing trip, before seeing the event, he met a man who hosted a music radio show in the city where Fienberg lives. The radio host was an eclipse chaser, and Fienberg said he'd never heard the host talk about astronomy on his show.

"I'm not interested in astronomy," the man told Fienberg. "I'm interested in beauty."

"That that told me right then on my first trip, this isn't just about astronomy," Fienberg said. "This is about beauty. This about being out in nature and being one with the universe — I mean it sounds silly! But you really feel like you're just part of it all and you're privileged to be able to see such a beautiful thing."

The unified message from Fienberg, NASA, the AAS and many other sources regarding the upcoming eclipse: Observe safely, and get to the path of totality on Aug. 21, 2017!

Follow Calla Cofield @callacofield. Follow us @Spacedotcom, Facebook and Google+. Original article on Space.com.

NASA's Parker Probe Will Explore The Sun's Hellish Atmosphere in 2018

NASA's Parker Probe Will Explore The Sun's Hellish Atmosphere in 2018:

NASA's Parker Solar Probe will fly closer to the sun than any spacecraft in history, and help scientists unlock secrets of our nearest star.

Credit: Johns Hopkins University Applied Physics Laboratory

Paul Sutter is an astrophysicist at The Ohio State University and the chief scientist at COSI Science Center. Sutter leads science-themed tours around the world at AstroTouring.com. 

By now, with so little time left until a total solar eclipse crosses the U.S. from coast to coast on Monday (Aug. 21), skywatchers planning to attend the event should understand that it's dangerous to look directly at the sun with the unaided eye, even if it's almost entirely covered by the moon. Seriously, don't do it.

The intense radiation emitted by the sun at multiple wavelengths, from the infrared through the ultraviolet, heats and warms our little world, but even at a distance of 93 million miles (149 million kilometers) and through our thick atmosphere, it can damage our skin and eyes. And occasionally make it possible to cook eggs on the sidewalk, if you're the adventurous sort.

So, NASA is going to send a spacecraft closer than ever before, and hope to capture useful data before the probe…well, melts.

The Parker Solar Probe was named after astrophysicist Eugene Parker (and let me interrupt myself and take this opportunity to castigate NASA for missing the golden opportunity to christen it the Icarus). The mission is set to launch in the summer of 2018. The craft won't take long to start taking dips near the sun, coming within 3.7 million miles (6 million km) of the surface. That sounds like a pretty large distance, which might lead some people to think the probe isn't getting that close to the sun — but the spacecraft will experience the sun's inferno at a scale 520 times greater than us here on Earth.

That mission design will continuously dip the probe in and out of the danger zone, coming seven times closer to the sun than any spacecraft before it. That puts poor Parker squarely within the sun's corona, the poorly understood wispy outer layer of our star. The hope is that this Evel Knievel-inspired plan will help us unlock the mysteries of that outer layer.

How does the corona reach temperatures exceeding 3 million degrees Fahrenheit (6 million Celsius), despite extending so far from the relatively cool surface? How do charged particles emanating from the sun get accelerated to near-light speed before spilling out into the system as a continuous solar wind? How do magnetic fields twist and tangle to transfer such tremendous energies?

We currently just have fuzzy half-answers to the above questions, and it's only by taking direct measurements as close to the furnace as possible that we can make more progress in answering them.

If you're lucky enough to see totality during the upcoming eclipse, you'll get to witness the sun's corona for yourself. And starting next year, plucky little Parker will be soon swimming in that sweltering soup, bravely collecting data before it, too, succumbs to the flames.

Follow us @Spacedotcom, Facebook and Google+. Original article on Space.com.

NASA's Epic Voyager Mission at 40: Q&A with Lead Scientist Ed Stone

NASA's Epic Voyager Mission at 40: Q&A with Lead Scientist Ed Stone:

Voyager 1 image of Jupiter's volcanic moon Io, showing the active plume of a volcano called Loki. 

Credit: NASA/JPL/USGS

NASA's historic Voyager mission has now been exploring the heavens for four decades.

The Voyager 2 spacecraft launched on Aug. 20, 1977, a few weeks before its twin, Voyager 1. Together, the two probes conducted an unprecedented "Grand Tour" of the outer solar system, beaming home up-close looks at Jupiter, Saturn, Uranus, Neptune and many of the moons of these giant planets.

This work revealed a jaw-dropping diversity of worlds, fundamentally reshaping scientists' understanding of the solar system. And then the Voyagers kept on flying. In August 2012, Voyager 1 became the first spacecraft ever to reach interstellar space — and Voyager 2 is expected to arrive in this exotic realm soon as well. [Voyager at 40: 40 Photos from NASA's Epic 'Grand Tour' Mission]

Ed Stone has served as Voyager project scientist since the mission's inception back in 1972. Space.com recently caught up with Stone, who talked about the 40-year anniversary, Voyager's greatest accomplishments and the mission's legacy.

Space.com: How does this 40-year milestone make you feel? What are your biggest impressions?

Voyager project scientist Ed Stone discusses the mission at NASA Headquarters in Washington, D.C., in April 2011.

Credit: NASA/Carla Cioffi


Ed Stone: It's amazing that the two spacecraft are still working after 40 years. When we launched, the Space Age itself was only 20 years old, so this is an unparalleled journey, and we're still in the process of discovering what's out there. Voyager 1 is out there in interstellar space; Voyager 2 is still inside, and we're seeing what's happening to the solar wind as it approaches interstellar space.

Space.com: Do you have an idea of when Voyager 2 will pop free into interstellar space?

Stone: Voyager 1 actually left the heliosphere in the nose region — that is, the region that faces into the interstellar wind, so that's the shortest way out. Voyager 2 is off to the flank of where the wind direction is, so the distance will be different. We don't know exactly how much different, because the models are not accurate enough to tell us that. But we can kind of estimate it from what Voyager 1 saw as it was approaching the boundary, the heliopause, and that suggests maybe several [more] years.

Space.com: What has Voyager 1 taught us about interstellar space so far?

Stone: It's really telling us how the interstellar wind interacts with the solar wind. Each star has wind blowing radially out from it. In the case of the sun, it's called the solar wind; it's the atmosphere of the sun speeding away in a million-mile-per-hour wind, which creates a bubble around the heliosphere. The bubble's size is determined by how much pressure there is from the interstellar wind outside, which came from explosive supernovae.

So there's a big difference between being inside, where the wind is from the sun and the magnetic field is from the sun, and being outside, where the wind is from the explosion over millions of years of supernovae, and where the magnetic field is the magnetic field of the Milky Way galaxy itself. [Voyager 1's Road to Interstellar Space: A Photo Timeline]

Another thing we've learned is how intense the cosmic radiation is out there. Cosmic rays are the nuclei of atoms that were accelerated by supernova explosions to nearly the speed of light. The fastest ones can easily get in to Earth; they were discovered here over 100 years ago. But the slower ones, the ones that are moving only 5 percent the speed of light or less, can't get in. And so we had no idea what the intensity of the cosmic radiation was outside the bubble.

We now know. The amount that gets in depends on the solar cycle, but we can say that less than a quarter of what's outside gets in. So the heliosphere is basically a radiation shield for all the planets, because it can exclude three-quarters of what's outside from getting in. We'll continue to monitor those cosmic rays now that we're out there, and we expect that Voyager 2 will find exactly the same story. If it doesn't, that will be a major surprise, because we think it's a pretty uniform environment now that we're outside.

Space.com: That was one of the mission's biggest accomplishments, obviously — reaching interstellar space and studying the environment there. Which of Voyager's other achievements stand out to you? Do you have any favorites?

Stone: Yes, I have a lot of favorites, actually! But I always like to think of Io, because it really set the stage for what was ahead. Io is a moon of Jupiter, and it's about the size of our moon. Before Voyager, the only known active volcanoes were here on Earth. And then we flew by Io with Voyager 1 and discovered eight erupting volcanoes — 10 times the volcanic activity of Earth, on this small moon. And it really set the stage for the fact that we were on a mission of discovery; we hadn't imagined the sorts of things we would be seeing.

Another one: In orbit around the same planet is Europa, which has an icy crust. It's again about the size of our moon. There are no volcanoes on Europa, but it has an icy crust which is cracked and certainly suggested that there could be a liquid-water ocean beneath. And again, before Voyager, the only oceans that were known were right here on Earth. It turned out, when [NASA's] Galileo [spacecraft] returned some years later and orbited [Jupiter] a number of times — it was able to show there was indeed a water ocean beneath the icy crust. [Photos: Europa, Mysterious Icy Moon of Jupiter]

Those are sort of two that kicked off the journey. Then we flew by Saturn, and its [biggest] moon Titan. Again, the only nitrogen atmosphere that we'd found in the solar system up until then was here on Earth. And yet, when we got to Titan, it has an atmosphere which is 1.5 times the pressure of the atmosphere on Earth — higher pressure, denser and much colder, of course. It may in some important ways resemble what the Earth's atmosphere was like before life evolved and created the oxygen that we all breathe.

Space.com: Are there any other surprises that really jumped out at you?

Stone: Well, before Voyager, all the magnetic fields seen at planets were like the Earth's magnetic field. That is, the magnetic pole is near the rotational pole of a planet. That was, we thought, because the magnetic field is created by the rotation of the liquid material beneath a planet's surface; therefore, the alignment seemed quite reasonable. And then we flew by Uranus and found its magnetic pole was nearer the equator than it was to the pole of rotation. And the same came true at Neptune. So this was not just an accident; in fact, these giant planets can have magnetic fields quite distinctly different in their orientation than what we had found at Jupiter and Saturn and Earth and Mercury.

Space.com: So, we're at 40 years now. How much longer will the Voyagers be able to keep gathering data and beaming it home to Earth?

Stone: The power supply is the natural radioactive decay of plutonium-238, which creates heat, and that is converted to electricity with thermocouples. So we can predict fairly accurately how much power we have, and how much less power we'll have each year, because of radioactive decay — it's decaying away. Every year now, we're in a mode where we have to turn off something that uses 4 watts, because we will have 4 watts less next year than we have this year. We have about 10 years or so of power remaining until we have only enough to power the spacecraft itself, without any of the instruments. That's on the order of 10 years from now.

But even after we no longer have power to send any data back to Earth, the two Voyager spacecraft will continue their orbit around the Milky Way, around the center of the galaxy with all the stars. Every 225 million years, they will complete another orbit around the Milky Way. And they will be doing that for billions of years, long after the Earth has been enveloped by the red giant sun. They'll be our silent ambassadors, with messages about where the place was that sent them so many billions of years earlier. [Photos from NASA's Voyager 1 and 2 Probes]

Credit: Karl Tate, SPACE.com


Space.com: Can you imagine life without Voyager at this point? Or is it just such a part of you that it's impossible to place yourself in an existence that doesn't involve Voyager?

Stone: Voyager's been at the center of my career, that is for sure. And it has allowed me to work on other projects, other missions. We've just finished and delivered an instrument for the Parker Solar Probe, which will launch in July of next year. That's the probe that will drop in near the sun, step by step, getting closer and closer. It's really exciting — that's what I call the inner frontier. It's where the solar wind begins.

Space.com: How do you think future generations will remember Voyager? What will the mission's main legacy be?

Stone: I think what Voyager has done is reveal how diverse the planets and the moons and the rings, and the magnetic fields of the planets, are. Our terracentric view was just much narrower than, in fact, reality. And now, of course, we know about planetary systems around other stars. There are many of them out there, and we have not found any that look like this one. So once again, it even expands the variability and diversity of what there is to be learned.

I'm hoping that, although it's not clear that we can ever send a spacecraft to one of these other systems, we can certainly improve our capabilities to observe them and study them and search for any evidence that perhaps at least microbial life has evolved on at least some of those planets, as it has here on Earth.

Follow Mike Wall on Twitter @michaeldwall and Google+. Follow us @Spacedotcom, Facebook or Google+. Originally published on Space.com.

The Sun Is Literally Boiling, Releasing Balls of 'Hot Horror' Into Space

The Sun Is Literally Boiling, Releasing Balls of 'Hot Horror' Into Space:

An active region on the surface of the sun can be seen here releasing a solar flare. The image comes from NASA's Solar Dynamics Observatory.

Credit: NASA/SDO

Paul Sutter is an astrophysicist at The Ohio State University and the chief scientist at COSI Science Center. Sutter leads science-themed tours around the world at AstroTouring.com.

 Here it comes: Tomorrow (Aug. 21), a total solar eclipse will cross the United States from Oregon to South Carolina.

Although everyone in the U.S. will get to enjoy at least a partial eclipse (assuming there are no clouds blocking the sun), anyone within the roughly 70-mile-wide (113 kilometers) strip of totality will get to see an unusual site: As the moon completely covers the sun, the midafternoon sky will plunge into darkness, and the moon itself will be encased in a dancing ring of fire: the solar corona, the thin but tremendous atmosphere of the sun.

That corona is intimately tied to the sun's agitation level. You see, despite its placid appearance in our sky — an unfailing source of warmth and light — the sun is actually a roiling, boiling, frenzied inferno of extreme forces and energies. [What You'll See During the 2017 Total Solar Eclipse]

I'm not just using the word "boiling" as a creative metaphor. The sun is literally boiling. The sun is hot on the inside (the nuclear fusion core) and relatively cold on the outside (where it meets the vacuum of space). To transfer all the heat from the inside to the outside, the sun convects, meaning plumes of material near the core heat up, expand and buoyantly rise to the surface, where they cool, condense and slink back down to the depths.

Sitting atop this boiling cauldron are the sunspots — gaping wounds in the sun where invisible twisted ropes of magnetic fields puncture the surface. Occasionally, these magnetic fields over-tangle to the point of breaking, releasing tremendous amounts of energy in furious outbursts.

That energy rips plasma material straight out of the sun itself; its very guts get hurled into space. Most of the time, these "prominences" die back down, settling back onto the surface with no one the wiser.

Hot plasma and light can be seen erupting from the surface of the sun in this video taken by NASA’s Solar Terrestrial Relations Observatory on July 23, 2017.

Credit: NASA’s Goddard Space Flight Center/STEREO/Bill Thompson


But with sufficient energy, the material can completely separate from the sun and fling across the solar system. A massive ball of charged particles, with their attendant scrambled electric magnetic fields, get ready to sweep over unsuspecting targets.

So-called coronal mass ejections are usually harmless, because space is big and the Earth is small (relatively). However, sometimes, these horror balls cross our path and really mess up our afternoon plans. When they do, satellites are forced to go into low-power safe mode, as the ensuing electromagnetic storm is hard on delicate circuits, and astronauts have to avoid spacewalks.

On Earth's surface, we're protected by the planet's magnetic field, which funnels the charged particles into Earth's poles, giving us spectacular aurora light shows. But even then, those aren't the strongest possible storms. Severe ones can penetrate Earth's defensive force field, damaging our everyday electronics.

Thankfully, we haven't had a powerful blast like that since the mid-1800s. And double-thankfully, NASA has a network of satellites and telescopes, like the Solar Dynamics Observatory, that keep a careful eye on the sun and forecast the solar weather in our neck of the woods.

Editor's note: Visit Space.com for a live solar eclipse webcast Monday, courtesy of NASA, beginning at 12 p.m. EDT (1600 GMT).

Follow Paul @PaulMattSutter and facebook.com/PaulMattSutter. Follow us @Spacedotcom, Facebook and Google+. Original article on Space.com.

Another Nearby Red Dwarf Star System, Another Possible Exoplanet Discovered!

Another Nearby Red Dwarf Star System, Another Possible Exoplanet Discovered!:



In the past few years, there has been no shortages of extra-solar planets discoveries which orbit red dwarf stars. In 2016 and 2017 alone,  astronomers announced the discovery of a terrestrial (i.e. rocky) planet around Proxima Centauri (Proxima b), a seven-planet system orbiting TRAPPIST-1, and super-Earths orbiting the nearby stars of LHS 1140 (LHS 1140b), and GJ 625 (GJ 625b).

In what could be the latest discovery, physicists at the University of Texas Arlington (UTA) recently announced the possible discovery of an Earth-like planet orbiting Gliese 832, a red dwarf star just 16 light years away. In the past, astronomers detected two exoplanets orbiting Gliese 832. But after conducting a series of computations, the UTA team indicated that an additional Earth-like planet could be orbiting the star.

The study which details their findings, titled “Dynamics of a Probable Earth-mass Planet in the GJ 832 System“, recently appeared in The Astrophysical Journal. Led by Dr. Suman Satyal – a physics researcher, lecturer and laboratory supervisor at UTA – the team sought to investigate the stability of planetary orbits around Gliese 832 using a numerical and detailed phase-space analysis.

Artistic representation of the potentially habitable exoplanet Gliese 832c as compared with Earth. Credit: PHL/UPR Arecibo.

As indicated, two other exoplanets had been discovered around Gliese 832 in the past, including a Jupiter-like gas giant (Gliese 832b) in 2008, and the super-Earth (Gliese 832c) in 2014. In many ways, these planets could not be more different. In addition to their disparity in mass, they vary widely in terms of their orbits – with Gliese 832b orbiting at a distance of about 0.16 AU and Gliese 832c orbiting at a distance of 3 to 3.8 AU.

Because of this, the UTA team sought to determine if perhaps there was a third planet with a stable orbit between the two. To this end, they conducted numerical simulations for a three and four body system of planets with elliptical orbits around the star. These simulations took into account a large number of initial conditions, which allowed for  all possible states (aka. s phase-space simulation) of the planet’s orbits to be represented.

They then included the radial velocity measurements of Gliese 832, accounting for them based on the presence of planets with 1 to 15 Earth masses. The Radial Velocity (RV) method, it should be noted, determines the existence of planets around a star based on variations in the star’s velocity. In other words, the fact that a star is moving back and forth indicates that it is being influenced by the presence of a planetary system.

Simulating the star’s RV signal using a hypothetical system of planets also allowed the UTA team to constrain the average distances at which these planets would orbit the star (aka. their semi-major axes) and their upper mass-limits. In the end, their results provided strong indications for the existence of a third planet. As Dr. Satyal explained in a UTA press release:

“We also used the integrated data from the time evolution of orbital parameters to generate the synthetic radial velocity curves of the known and the Earth-like planets in the system. We obtained several radial velocity curves for varying masses and distances indicating a possible new middle planet.”

Diagram showing the possible orbit of a third exoplanet around Gliese 832, a star system located just 16 light years away. Credit: uta.edu/Suman Satyal

Based on their computations, this possible planet of the Gliese 832 system would be between 1 and 15 Earth masses and would orbit the star at a distance ranging from 0.25 to 2.0 AU. They also determined that it would likely have a stable orbit for about 1 billion years. As Dr. Satyal indicated, all signs coming from the Gliese 832 system point towards there being a third planet.

“The existence of this possible planet is supported by long-term orbital stability of the system, orbital dynamics and the synthetic radial velocity signal analysis,” he said. “At the same time, a significantly large number of radial velocity observations, transit method studies, as well as direct imaging are still needed to confirm the presence of possible new planets in the Gliese 832 system.”

Alexander Weiss, the UTA Physics Chair, also lauded the achievement, saying:

“This is an important breakthrough demonstrating the possible existence of a potential new planet orbiting a star close to our own. The fact that Dr. Satyal was able to demonstrate that the planet could maintain a stable orbit in the habitable zone of a red dwarf for more than 1 billion years is extremely impressive and demonstrates the world class capabilities of our department’s astrophysics group.”

Artist’s impression of a Super-Earth orbiting close to a red dwarf star. Credit: M. Weiss/CfA

Another interesting tidbit is that this planet’s orbit would place it beyond or just within Gliese 832’s habitable zone. Whereas the Super-Earth Gliese 832c has an eccentric orbit that places it at the inner edge of this zone, this third planet would skirt its outer edge at the nearest. In this sense, Gliese 832’s two Super-Earths could very well be Venus-like and Mars-like in nature.

Looking ahead, Dr. Satyal and his colleagues will be naturally be looking to confirm the existence of this planet, and other institutions are sure to conduct similar studies. This star system is yet another that is sure to be the subject of follow-up studies in the coming years, most likely from next-generation space telescopes like the James Webb Space Telescope.

Further Reading: University of Texas Arlington, The Astrophysical Journal

The post Another Nearby Red Dwarf Star System, Another Possible Exoplanet Discovered! appeared first on Universe Today.

NGC 2442: Galaxy in Volans

NGC 2442: Galaxy in Volans:

Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.

2017 August 17

Explanation: Distorted galaxy NGC 2442 can be found in the southern constellation of the flying fish, (Piscis) Volans. Located about 50 million light-years away, the galaxy's two spiral arms extending from a pronounced central bar have a hook-like appearance in wide-field images. But this mosaicked close-up, constructed from Hubble Space Telescope and European Southern Observatory data, follows the galaxy's structure in amazing detail. Obscuring dust lanes, young blue star clusters and reddish star forming regions surround a core of yellowish light from an older population of stars. The sharp image data also reveal more distant background galaxies seen right through NGC 2442's star clusters and nebulae. The image spans about 75,000 light-years at the estimated distance of NGC 2442.

Perseids over the Pyrenees

Perseids over the Pyrenees:

Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.

2017 August 18

Explanation: This mountain and night skyscape stretches across the French Pyrenees National Park on August 12, near the peak of the annual Perseid meteor shower. The multi-exposure panoramic view was composed from the Col d'Aubisque, a mountain pass, about an hour before the bright gibbous moon rose. Centered is a misty valley and lights from the region's Gourette ski station toward the south. Taken over the following hour, frames capturing some of the night's long bright perseid meteors were aligned against the backdrop of stars and Milky Way.

Total Solar Eclipse of 1979

Total Solar Eclipse of 1979:

Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.

2017 August 19

Total Solar Eclipse of 1979

Image Credit & Copyright: Jimmy Westlake (Colorado Mountain College)


Explanation: From cold, clear skies over Riverton, Manitoba, Canada, planet Earth, the solar corona surrounds the silhouette of the New Moon in this telescopic snapshot of the total solar eclipse of February 26, 1979. Thirty eight years ago, it was the last total solar eclipse visible from the contiguous United States. The narrow path of totality ran through the northwestern states of Washington, Oregon, Idaho, Montana, and North Dakota before crossing into Canadian provinces Saskatchewan, Manitoba, Ontario and Quebec. Following the upcoming August 21, 2017 total solar eclipse crossing the U.S. from coast to coast, an annular solar eclipse will be seen in the continental United States on October 14, 2023, visible along a route from Northern California to Florida. Then, the next total solar eclipse to touch the continental U.S. will track across 13 states from from Texas to Maine on April 8, 2024.

Tomorrow's picture: eclipse eve

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Why the Total Solar Eclipse Arrives from the West

Why the Total Solar Eclipse Arrives from the West:

The moon's shadow, projected on Earth during a total solar eclipse, as seen from space. While the moon normally rises in the east and sets in the west, a total solar eclipse moves from west to east.

Credit: NASA/DSCOVR-EPIC Team

Paul Sutter is an astrophysicist at The Ohio State University and the chief scientist at COSI Science Center. Sutter leads science-themed tours around the world at AstroTouring.com. 

Every day, the same routine. The sun rises in the east. Breakfast. Off to work. Work. Home from work. Dinner. The sun sets in the west. Repeat. It's a pattern familiar to everyone on Earth. For countless generations, we've relied on the regular cycles of the heavens to help demarcate our days.

But a total solar eclipse, like the big one coming to the continental United States on Aug. 21, will break the routine. In addition to the moon completely covering the face of the sun — which, let's admit, is already pretty spectacular — the event will move in an unfamiliar and possibly disquieting direction: from west to east.  [Total Solar Eclipse 2017: When, Where and How to See It (Safely)]

The normal, daily rising and setting of celestial objects isn't due to their own movement, but rather the rotation of Earth. As our planet spins on its axis, the heavens appear to rise up from the east, arch their way across the sky, and settle into the west.

It's hard to blame our ancestors for assuming that Earth — which seemed very large and strong — was incapable of movement, with the ethereal denizens of the heavens gliding along their nested crystal spheres, giving humans our familiar, clockwork celestial movements.

After centuries of serious work, people realized that Earth does indeed spin, and the motion of the sun, moon and stars is only apparent. But when it comes to solar eclipses we're faced with a new incongruity: why does the path of a solar eclipse start in the west and end in the east?

The answer is simple, but it's not something we're accustomed to thinking about: the moon itself orbits Earth from west to east. In other words, if you could rocket up high above the North Pole, the moon would trace out a counterclockwise circle. But Earth rotates about 30 times for a single lunar orbit, so it's not something we normally notice. During a solar eclipse, the path of the moon's shadow must follow the motion of the moon itself — to the east.

The solar eclipse is a wonderful opportunity to experience astronomy at its most basic: understanding the intricate dance of heavenly objects.

Follow us @Spacedotcom, Facebook and Google+. Original article on Space.com.

Next Stop for Parkinson's Disease Research: Outer Space

Next Stop for Parkinson's Disease Research: Outer Space:

The International Space Station as seen in a photo taken in 2010.

Credit: NASA

In an effort to find new treatments for Parkinson's disease, researchers are sending their experiments to space.

This Monday (Aug. 14), researchers will launch a key Parkinson's disease protein, called LRRK2, to the International Space Station (ISS). The microgravity conditions in space should offer a better test environment for their experiments with this protein, the researchers said.

The materials for their experiments will travel aboard the SpaceX Dragon capsule as part of a mission to send supplies and science experiments to the ISS.

The work is a collaboration between The Michael J. Fox Foundation for Parkinson's Research and the Center for the Advancement of Science in Space (CASIS).

LRRK2 is a type of protein that modifies other proteins. Mutations in the gene that codes for LRRK2 are thought to cause Parkinson's disease in some people. Researchers have hypothesized that developing drugs to inhibit LRRK2, or block its activity, could help prevent Parkinson's or slow its progression. [10 Celebrities with Chronic Illnesses]

But before scientists can develop a drug to inhibit LRRK2, they need to know the precise structure of this protein. One way to get a detailed view of its structure is by growing crystals of LRRK2 in lab dishes. However, on Earth, gravity can interfere with the growth of these crystals, and keep them small.

"The quality of our crystals is just not good enough [on Earth]," Sebastian Mathea, a researcher at the University of Oxford who is involved in the LRRK2 project, said during a news conference about the project Tuesday (Aug. 8).

This is where the ISS research comes in: Researchers hope that the microgravity conditions in space will allow the crystals to grow bigger with fewer defects. The scientists can then get a sharper view of the crystal structure.

Scientists will grow the LRRK2 crystals for about a month in space. Then, the crystals will be sent back to Earth, where they will be analyzed with high-energy X-rays, Mathea said.

Parkinson's disease is a progressive neurological disorder that affects people's movement abilities, and can result in symptoms such as tremors, slowed movements and muscle stiffness. There are currently no treatments to stop or reverse the progression of the disease, according to The Michael J. Fox Foundation.

Original article on Live Science.

Ancient Pueblo Rock Art Depicts a 'Celebratory' Solar Eclipse

Ancient Pueblo Rock Art Depicts a 'Celebratory' Solar Eclipse:

The rock art depicting a solar eclipse, possibly from A.D. 1097, looked "more celebratory than frightening," said a University of Colorado archaeoastronomer.

Credit: J Mckim Malville/University of Colorado

Millions of people will gaze at the Great American Eclipse on Aug. 21, shooting photographs and taking selfies. A thousand years ago, early Pueblo people, called Chacoans, captured their experiences of a total solar eclipse by carving it into a rock — a circle with looping streamers that resemble the sun's outer atmosphere, or corona.

Not only does this rock art, or petroglyph, depict a solar eclipse with a gigantic eruption of plasma called a coronal mass ejection (CME), its looping lines may have evoked a wondrous, inspirational experience, said solar astronomer J. McKim Malville, a University of Colorado Boulder professor emeritus, who is an expert in archaeoastronomy.

"The petroglyph looks more celebratory than frightening," Malville told Live Science. "If our interpretation is correct, they tried to depict the extraordinary sight of the corona, like nothing seen before — associated [it] with a deity that was even more mysterious and powerful than they imagined." [See Photos of the Petroglyph of the Solar Eclipse]

Malville discovered the petroglyph in 1992, while on a scientific excursion into Chaco Canyon, New Mexico, with W. James Judge, then a professor of anthropology at Fort Lewis College in Colorado. They found the petroglyph among others pecked into a large boulder called Piedra del Sol, near the ruins of a cultural hub for the Chacoans, who thrived there between A.D. 900 and 1150.

A petroglyph found in Chaco Canyon in New Mexico depicts a solar eclipse with a huge coronal mass ejection (an eruption of plasma from the sun).

Credit: J Mckim Malville/University of Colorado


When he saw it, Malville immediately recognized something familiar.

"Some people might see it as a bug or a tick or a spider," he said. "But it struck me as very similar to photographs of coronal mass ejections that I'd seen, and drawings."

In 2014, Malville and professor José Vaquero of the University of Extremadura in Cáceres, Spain, published a study in the Journal of Mediterranean Archaeology and Archaeometry describing the discovery. They knew that an eclipse had occurred in the region on July 11, 1097, and that the sun's corona and even CMEs are visible to the naked eye during totality (when the moon's shadow completely blocks the sun's light from reaching Earth). But they needed evidence that the sun was in a period of heightened activity, known as solar maximum, when such ejections are most common. It occurs about every 11 years or so, with some variation in the intensity, Malville said.

He and his colleague consulted several sources to determine the level of activity around the time of the eclipse. They looked at data from ancient tree rings, which store traces of atmospheric carbon from photosynthesis and also provide a natural calendar of annual growth. During periods of high solar activity, the sun's more intense magnetic fields deflect cosmic rays from reaching Earth, reducing the amount of radioactive carbon, found as isotope carbon-14, in tree rings. For the period around 1097, the carbon-14 isotopes were low.

Naked-eye observations of sunspots recorded in ancient Chinese texts also indicated higher solar activity, as did historical data from northern Europeans on the annual number of so-called "auroral nights." The evidence pointed to high levels of activity on the sun during the 1097 eclipse. [The 8 Most Famous Solar Eclipses in History]

"It turns out, the sun was in a period of very high solar activity at that time, consistent with an active corona and CMEs," Malville said in news statement.

The depiction itself, a circle with looping streamers radiating from the edge, struck Malville as something jubilant, not frightening.

There are cultures that consider eclipses as dangerous and fearsome omens during the moments when the day turns into "night," Malville said.

But not all.

He recalled viewing the June 30, 1972, eclipse in Kenya, camped at the eastern edge of Lake Turkana among Turkana, Samburu and El Molo tribes. During the eclipse, the El Molo went into their huts, as they do every evening, remaining there until light returned; they didn't seem influenced at all by the event, he said. But the other tribes came to the campsite to view the eclipse.

This particular event lasted 7 minutes, an unusually long time, and the people there had a chance to see the beauty of the corona during totality.

"The brightness of the corona is about the brightness of the full moon, so it's easily seen with the naked eye," Malville said. (REMEMBER, never look directly at the sun or a solar eclipse without special protective viewers, though you can look at the eclipse without glasses ONLY during the couple of minutes of totality.)

Afterward, the people performed dances to celebrate the eclipse and thank the astronomers for the chance to see it.

Malville thinks that the 1097 eclipse in Chaco Canyon may have stirred a similar sense of wonder in the early Pueblo people. After 1100, the people built 10 large houses, called the Great Houses in Chaco, all of which are in areas that provide dramatic views of the rising or setting sun at the winter or summer solstices, he said.

"There is the possibility that the glory of that experience for the people living in Chaco in 1097 was transformed to an increased reverence for or an increased appreciation of the sun," Malville said.

He has a theory about why some modern people might claim that ancient civilizations were terrified by eclipses.

"They have never seen the full glory of an eclipse themselves," he said.

Originally published on Live Science.

Is Dark Matter Less 'Lumpy' Than Predicted?

Is Dark Matter Less 'Lumpy' Than Predicted?:

Composite picture of stars over the Cerro Tololo Inter-American Observatory in Chile.

Credit: Reidar Hahn/Fermilab

Don Lincoln is a senior scientist at the U.S. Department of Energy's Fermilab, the country's largest Large Hadron Collider research institution. He also writes about science for the public, including his recent "The Large Hadron Collider: The Extraordinary Story of the Higgs Boson and Other Things That Will Blow Your Mind" (Johns Hopkins University Press, 2014). You can follow him on Facebook. Lincoln contributed this article to Live Science's Expert Voices: Op-Ed & Insights.

For as long as we have kept records, humanity has marveled at the night sky. We have looked at the heavens to determine the will of the gods and to wonder about the meaning of it all. The mere 5,000 stars we can see with the unaided eye have been humanity’s companions for millennia.

Modern astronomical facilities have shown us that the universe doesn't consist of just thousands of stars — it consists of hundreds of billions of stars in our galaxy alone, with trillions of galaxies. Observatories have taught us about the birth and evolution of the universe. And, on Aug. 3, a new facility made its first substantive announcement and added to our understanding of the cosmos. It allows us to see the unseeable, and it showed that the distribution of matter in the universe differed a bit from expectations.

The Dark Energy Survey (DES) is a collaboration of about 400 scientists who have embarked on a five-year mission to study distant galaxies to answer questions about the history of the universe. It uses the Dark Energy Camera (DEC) attached to the Victor M. Blanco 4-meter telescope at the Cerro Tololo Inter-American Observatoryin the Chilean Andes. DEC was assembled in the U.S. at Fermilab near Batavia, Illinois, and is a 570-megapixel camera able to image galaxies so far away that their light is a millionth as bright as the dimmest visible stars.

Dark energy and dark matter

DES is hunting for dark energy, which is a proposed energy field in the universe that is a repulsive form of gravity. While gravity exerts an irresistible attraction, dark energy pushes the universe to expand at an ever-increasing rate. Its effect was first observed in 1998, and we still have many questions about its nature.

However, by measuring the location and distance of 300 million galaxies in the southern night sky, the survey will be able to make important statements about another astronomical mystery, called dark matter. Dark matter is thought to be five times more prevalent in the universe than ordinary matter. Yet it doesn’t interact with light, radio waves or any form of electromagnetic energy. And it doesn’t appear to congregate to form large bodies like planets and stars.

Map of dark matter made from gravitational lensing measurements of 26 million galaxies in the Dark Energy Survey.

Credit: Chihway Chang of the Kavli Institute for Cosmological Physics at the University of Chicago and the DES collaboration


There is no way to directly see dark matter (hence the name). However, its effects can be seen indirectly by analyzing how fast galaxies rotate. If you calculate the rotational speeds supported by the galaxies’ visible mass, you will discover that they rotate more quickly than they should. By all rights, these galaxies should be torn apart. After decades of research, astronomers have concluded that each galaxy contains dark matter, which generates the additional gravity that holds the galaxies together. [6 Weird Facts About Gravity]

Dark matter in the universe

However, on the much larger scale of the universe, studying individual galaxies is not sufficient. Another approach is needed. For that, astronomers must employ a technique called gravitational lensing.

Gravitational lensing was predicted in 1916 by Albert Einstein and was first observed by Sir Arthur Eddington in 1919. Einstein’s theory of general relativity says that the gravity that we experience is really caused by the curvature of space-time. Since light travels in a straight line through space, if space-time is curved, it will look to an observer as if light were travelling a curved path through space. [8 Ways You Can See Einstein's Theory of Relativity in Real Life]

This phenomenon can be harnessed to study the amount and distribution of dark matter in the universe. Scientists who peer at a distant galaxy (called the lensing galaxy), which has another galaxy even farther away behind it (called the observed galaxy), can see a distorted image of the observed galaxy. The distortion is related to the mass of the lensing galaxy. Because the mass of the lensing galaxy is a combination of visible matter and dark matter, gravitational lensing allows scientists to directly observe the existence and distribution of dark matter on scales as large as the universe itself.  This technique also works when a large cluster of foreground galaxies distorts the images of clusters of even more distant galaxies, which is the technique employed for this measurement.

Lumpy or not?

The DES collaboration recently released an analysis using exactly this technique. The team looked at a sample of 26 million galaxies at four different distances from Earth. The closer galaxies lensed ones that were farther away. By using this technique and looking carefully at the distortion of the images of all of the galaxies, they were able to map out the distribution of invisible dark matter and how it moved and clumped over the past 7 billion years, or half the lifespan of the universe.

As expected, they found that the dark matter of the universe was "lumpy." However, there was a surprise — it was a little less lumpy than previous measurements had predicted.

One of these contradictory measurements comes from the remnant radio signal from the earliest time after the Big Bang, called the cosmic microwave background (CMB). The CMB contains within it the distribution of energy in the cosmos when it was 380,000 years old. In 1998, the Cosmic Background Explorer (COBE) collaboration announced that the CMB was not perfectly uniform, but rather had hot and cold spots that differed from uniform by 1 part in 100,000. The Wilkinson Microwave Anisotropy Probe (WMAP) and Planck satellites confirmed and refined the COBE measurements.

Over the 7 billion years between when the CMB was emitted and the time period studied by DES, those hotter regions of the universe seeded the formation of structure of the cosmos. Nonuniform energy distribution captured in the CMB, combined with the amplifying force of gravity, caused some spots in the universe to become denser and others less so. The result is the universe we see around us.

The CMB predicts the distribution of dark matter for a simple reason: The distribution of matter in our universe in the present depends on its distribution in the past. After all, if there were a clump of matter in the past, that matter would attract nearby matter and the clump would grow. Similarly, if we were to project into the distant future, the distribution of matter today would affect tomorrow's for the same reason.

So, scientists have used measurements of the CMB at 380,000 years after the Big Bang to calculate what the universe should look like 7 billion years later. When they compared the predictions to the measurements from DES, they found that the DES measurements were a little less lumpy than the predictions.

Incomplete picture

Is that a big deal? Maybe. The uncertainty, or error, in the two measurements is big enough that it means they don’t disagree in a statistically significant way. What that simply means is that no one can be sure that the two measurements really disagree. It could be that the discrepancies arise by chance from statistical fluctuations in the data or small instrumental effects that were not considered.

Even the study’s authors would suggest caution here. The DES measurements have not yet been peer-reviewed. The papers were submitted for publication and the results were presented at conferences, but firm conclusions should wait until the referee reports come in.

So, what is the future? DES has a five-year mission, of which four years of data have been recorded. The recently announced result uses only the first year’s worth of data. More recent data is still being analyzed. Further, the full data set will cover 5,000 square degrees of the sky, while the recent result only covers 1,500 square degrees and peers only half of the way back in time. Thus, the story is clearly not complete. An analysis of the full data set won’t be expected until perhaps 2020.

Yet, the data taken today already could mean that there is a possible tension in our understanding of the evolution of the universe. And, even if that tension disappears as more data is analyzed, the DES collaboration is continuing to make other measurements. Remember that the letters "DE" in the name stand for dark energy. This group will eventually be able to tell us something about the behavior of dark energy in the past and what we can expect to see in the future. This recent measurement is just the very beginning of what is expected to be a scientifically fascinating time.

Follow all of the Expert Voices issues and debates — and become part of the discussion — on Facebook, Twitter and Google+. The views expressed are those of the author and do not necessarily reflect the views of the publisher.

This version of the article was originally published on Live Science.

Summer Triangle: Asterism of 3 Stars From 3 Constellations

Summer Triangle: Asterism of 3 Stars From 3 Constellations:

In this image we can see the asterism of the "Summer Triangle" a giant triangle in the sky composed of the three bright stars Vega (top left), Altair (lower middle) and Deneb (far left).

Credit: A. Fujii

The Summer Triangle is a Northern Hemisphere asterism (stars of similar brightness recognized in a distinctive shape). Unlike many other asterisms, the Summer Triangle is actually an amalgamation of stars from three separate constellations.

Three stars make up the triangle: Deneb, Vega and Altair. Deneb is the farthest away from Earth among these three, and is the brightest star in the constellation Cygnus; it forms the tail of the Swan. Coincidentally, Deneb is also the head of another asterism known as the Northern Cross, which is contained in Cygnus.

Vega is the brightest star of an otherwise dim and small constellation, Lyra (the Harp). Vega is one of the brightest stars in the night sky. (Sirius is the brightest in the night sky, but appears in the winter of the Northern Hemisphere.) About 12,000 years ago, it used to be the North Star due to an effect called precession, where the Earth's north-pointing direction changes due to a wobbling axis.

Rounding out the asterism is Altair, which is the brightest star in the constellation Aquilia (the Eagle.) Altair is one of the brightest close stars to Earth.

Asterism popularized in the 1950s

Unlike other asterisms such as the Big Dipper or the Little Dipper, the Summer Triangle is a recently popularized term.

The three stars have been recognized for some time as having similar brightness (although it should be noted that Deneb is about 1,400 light-years away while Vega and Altair are roughly 20 light-years away each, showing how much more luminous Deneb is.) [Related: Brightest Stars: Luminosity & Magnitude]

“It's appeared in various works for generations,” said Tom Kerss, an astronomer at the Royal Observatory Greenwich, in a Space.com interview. “Johann Bode traced the Summer Triangle in his star maps to the early 19th century, but it was unlabelled. It was then recognized as a way of navigating.”

A rough approximation of the term appears in works by Oswald Thomas, an Austrian astronomer, who referred to it as “Sommerliches Dreieck” (the Summerly Triangle) in the 1930s, Kerss added. Then in the 1950s, two astronomy popularizers picked up the term and made it generally known in the public: H.A. Rey in the United States and Patrick Moore in the United Kingdom.

Lie back on a warm summer night and look straight up. You’ll see three bright stars: Vega, Deneb, and Altair. These mark the corners of the “Summer Triangle” and are your guides to the three constellations of Lyra, Cygnus, and Aquila.

Credit: Starry Night Software

Recent astronomical news

Vega was discovered to have an asteroid belt in 2013, leading astronomers to suggest that the star could host planets. Astronomers detected signs of icy asteroids in the outer regions of the star, and space rocks closer in. It was a similar signature to what was detected in another bright star in the sky, that of Fomalhaut.

"Overall, the large gap between the warm and the cold belts is a signpost that points to multiple planets likely orbiting around Vega and Fomalhaut," said Kate Su, an astronomer at the Steward Observatory at the University of Arizona, at the American Astronomical Society 2013 annual meeting.

Vega is also a fast rotater. In 2006, astronomers discovered it is whirling around so quickly — every 12.5 hours — that its equator is many thousand degrees cooler than its poles. If the star rotated just 10 percentage points faster, it would be at its critical rotation speed — the point at which the star would self-destruct due to its fast rotation. The star is sometimes cited in the literature as a comparison to the rotation of other stars, such as the slowly rotating KIC 11145123.

Altair also rotates fairly quickly and has flattening at its poles, which astronomers spotted in 2006 using long-baseline interferometery (which links together numerous telescopes to together look at a region of the sky.) In 2014, the XMM-Newton mission observed Altair, showing that the star has a corona (outer atmosphere) that changes depending on magnetic and rotational activity.

Deneb, meanwhile, is on astronomers' watchlist as a probable future supernova. Because the star is so bright, it is sometimes used as a testing platform for new professional telescopes, or for simulating the positions of objects in astronomical pictures.

Additional resources

• The Stars website, created by Jim Kaler, professor emeritus of astronomy at the University of Illinois, has more information about the Summer Triangle.
• NASA's "Astronomy Picture of the Day" features a beautiful image of the Summer Triangle over Catalonia.
• Astronomer David Darling's Encyclopedia of Science has an entry on the Summer Triangle.

Solar Eclipses Through the Ages: From (Possible) Beheadings to Science

Solar Eclipses Through the Ages: From (Possible) Beheadings to Science:

Through the ages, people have documented total solar eclipses. Here, an artistic depiction of the July 29, 1878 total solar eclipse by E.L. Trouvelot.

Credit: New York Public Library

Paul Sutter is an astrophysicist at The Ohio State University and the chief scientist at COSI Science Center. Sutter leads science-themed tours around the world at AstroTouring.com. Sutter contributed this article to Space.com's Expert Voices: Op-Ed & Insights.

People enjoy looking at the sky. People enjoy writing down minute details of their daily lives. Ergo, when people see something interesting in the sky, they write it down. We have historic — and surprisingly, prehistoric — records of celestial events going back thousands of years, including solar eclipses. So when you pick just the right Instagram filter for your "solar selfie" this Aug. 21, you're following in the footsteps of an ancient and noble tradition. (Note: Do not photograph an eclipse without a safe solar filter when any portion of the sun is visible.)

Due to their very nature, prehistoric records of solar eclipses are the hardest to interpret. Does that swirly thing represent the sun? Are the concentric circles the full moon? The new moon? And what about those zigzags? If we're correctly interpreting the petroglyphs on the ancient monuments near Loughcrew, Ireland, then the oldest recorded solar eclipse dates to 3340 B.C.

Once we enter written history things get a little more reliable. A peculiar tale comes down to us telling the story of Chinese Emperor Chung K'ang, who apparently beheaded his court astronomers for failing to predict the eclipse of 2137 B.C. While the anecdote may be purely apocryphal, it is a good way to frighten young astronomers around the campfire.  [Total Solar Eclipse 2017: When, Where and How to See It (Safely)]

I should mention that the Chinese went on to record nearly a thousand eclipses from the eighth century B.C. until the fifth century B.C., with no associated beheadings reported.

They weren't alone, however. The Babylonians and Greeks busied themselves recording solar eclipses, using colorful language like "the sun was put to shame," as one ancient clay tablet attests. Solar eclipses were too hard to predict with any degree of confidence with the limited accuracy available to the ancients — poor consolation to the Chinese court astronomers, I know — but as far as we can tell, all the civilizations that kept track of eclipses quickly realized that they were a result of the natural motions of the sun and moon.

That said, the astrological worldview posited that the motions of the heavens were connected to earthly events, so solar eclipses weren't necessarily to be feared (at least, by the intelligentsia of their respective cultures), but were used to read the fortunes of emperors, generals, religious leaders and other important folk. [10 Solar Eclipses That Changed Science]

Entering the scientific era of astronomy, solar eclipses began to be used for more than just finding a tenuous connection to the fortunes of the big boss. Observers began to study the corona in more detail, discovering helium (Helios, like the Greek god of the sun — get the name now?) in the process. Later on, they would be used to verify the prediction of general relativity that massive objects can bend the path of light.

These days, as on Aug. 21, they will be an opportunity to ooh and ah at the beauty of the natural world while simultaneously doing research. And no beheadings.

Follow Paul @PaulMattSutter and facebook.com/PaulMattSutter. Follow us @Spacedotcom, Facebook or Google+. Originally published on Space.com.

The Mars Colony of the Future Could Be Powered by This Advanced Microgrid

The Mars Colony of the Future Could Be Powered by This Advanced Microgrid:

Credit: 3quarks

SpaceX and Tesla CEO Elon Musk wants to put a million people on Mars in the next century. They'll be ferried to the Red Planet on a fleet of spaceships that can each carry 100 or more people, and make their living in an environment bereft of oxygen and full of danger.

While you can't breathe the air on Mars, with some creative thinking you could bring in many of the comforts of home. Mars has great potential for energy generation. While its atmosphere is dusty, the sun's light reaches down to the surface, allowing for solar panels. And the wind that provides the driving force of erosion on Mars could be harnessed for wind farms.

The industrial manufacturing giant Siemens is trying to plan for this reality.

"Mars will be the ultimate microgrid," the company says on its website. "With no centralized power sources, communities will one day rely on decentralized energy systems."

Their first major test case: an indigenous reservation about 5.5 hours north of San Francisco. The Blue Lake Rancheria is home to the Aboriginal Wiyot, encompassing members of the Wiyot, Yurok, Tolowa, and Cherokee tribes. It's a 91-acre area, with 53 members living among coastal mountains and large redwood trees.

While the area is rich in natural resources — unlike Mars — the Wiyot have endured regular interruptions with the Pacific Gas & Electric power grid in recent years. That's where Siemens stepped in.

"They got the idea that they wanted to do something about it, and their No. 1 objective was improve reliability, and… to reduce the carbon footprint," said Clark Wiedetz, director of microgrid and renewable integration at Siemens Energy Management.

The result is a microgrid, completed in April, that is expected to save the community more than $200,000 a year. It includes a 500-kilowatt array of solar panels that were designed and built by REC Solar, a Tesla battery storage system, and contributions from other partners. Siemens maintains the microgrid through a computer-operated management system that decides where best to allocate power resources.

"They have the ability to replace what power they take from the grid, when that makes sense or when it's down," Wiedetz said.

The Siemens system makes decisions about where to put the power, basing its analysis on historical data. If a storm were to knock out the power, for example, the microgrid would predict how much power is needed for the Red Cross shelter on site, and allocate resources accordingly.

"A colony on Mars may one day be powered by the types of on-site systems that are already hard at work on Earth," the company says.

Though a similar system could be the answer to sustaining power on Mars, it's hard to know right now what a Martian equivalent would need.

"We don't know what variables to work in the equation," Wiedetz explained. But he said the microgrid system does have some advantages. One big one is that it doesn't rely on cloud computing, which would likely not be in place on Mars. The Wiyot residents can also take on maintenance themselves, with remote assistance — just as astronauts would be expected to do so in deep space.

The microgrid system is adapted from previous software used for utility companies for energy management. It's a new use for the 20-year-old technology, and Wiedetz said Siemens is looking at other ways to implement it, but they're not yet ready to reveal where they plan to do so.

Tesla, which has positioned itself as a major player in battery development, has worked on other microgrids before. In 2016, the company announced that it and its subsidiary SolarCity helped the entire island of Ta’u in American Samoa. Thanks to a newly installed microgrid with solar panels and Tesla batteries, the island (which used to burn 100,000 gallons of fuel a year) could have full power for three days — even when it's cloudy.

Originally published on Seeker.