Sunday, August 20, 2017

Here's a Weather Update for Solar Eclipse Day (Aug. 21, 2017)

Here's a Weather Update for Solar Eclipse Day (Aug. 21, 2017):

Here's a Weather Update for Solar Eclipse Day (Aug. 21, 2017)
A cloudy partial solar eclipse.
Credit: Deacon MacMillan/Flickr

With eclipse day fast approaching, many people are obviously concerned about how the weather will impact their viewing. Here's how it's looking for locations all along the eclipse path. Before getting into this, however, I want to make sure anyone reading this acknowledges a "reality check" that this event is still three days away, and forecasters are not overly confident on some of the finer details. Over the weekend, this confidence will increase, especially as Monday comes into the time range of various shorter-term, higher-resolution computer models.

Pacific Northwest/Rocky Mountains/Northern Great Plains

The Oregon/Idaho/Wyoming part of the total eclipse path will experience a high-pressure ridge over the Pacific Northwest on Monday, according to the National Weather Service. There will also be a weak low off the Southern California coast that sends some monsoon moisture north from the desert Southwest — but all models keep the moisture south of the Oregon/Nevada border. That should ensure mostly clear skies for much of Oregon come Monday morning. The exception to this would be marine clouds coming onshore along Oregon's central coast. From a climatological point of view, however, marine clouds don't make it very far inland, so locations from the Coast Range eastward appear to have a very good chance of clear skies for the eclipse Monday morning.

For Idaho, haze and smoke could be present from area wildfires. It looks like the best cloud/storm chances will remain across the southern highlands and perhaps out of the totality path. [Solar Eclipse 2017: Traffic and Weather Forecasts for States in Totality]

As for Wyoming, the main weather concern for eclipse day will be a threat for scattered to occasionally broken cloud cover. For now, the consensus is a 30 to 60 percent cloud cover along the path of totality during the eclipse. Most of these clouds will be of the high and mid cloud variety with cumulus cloud buildups, mainly over the mountains, where only isolated shower or thunderstorm activity is expected.

Central Great Plains

Pushing into Nebraska/Kansas/Missouri and southern Illinois, the situation becomes more problematic, as a storm system is expected to move across northern Nebraska Monday morning. So those living near and along the totality path in Nebraska may have to deal with some potential storms and cloudiness early on Monday. The big question that we're focusing on right now is whether the clouds can clear enough later Monday morning after the rain in time for the eclipse.

Based on the latest guidance models, it seems that yes, there may be morning clouds and storms, but there's a decent chance that they will begin to scatter or break up by late morning. Obviously, trying to predict a cloud forecast with certainty for a 2-minute window that's still a few days away is a significant challenge.

Looking at Kansas and Missouri, this same unsettled weather system will be a factor. That, combined with a strong southerly wind, brings increasing low-level moisture for Sunday night into Monday. The GFS (Global Forecast System) and Canadian models are more bullish on rain and cloud-cover chances; this may be an issue for eclipse watchers.

But the Nebraska storm is expected to shift rapidly into Iowa by late Monday. As such, there is better support for good eclipse viewing for areas farther east into east-central and southeast Missouri, as well as southern Illinois, which should be farther away from what could be isolated thunderstorms. Western and central Missouri look to be in the worst spot in this four-state region. [Total Solar Eclipse 2017: When, Where and How to See It (Safely)]

Ohio and Tennessee valleys

Looking farther east at Kentucky and Tennessee, high pressure at the surface and aloft is expected to remain in place across the region. Kentucky looks to remain on the northern periphery of the ridge, and some of the model data suggest that isolated afternoon or evening storms could occur. Skies look to remain mainly clear in the morning, with cumulus clouds popping up during the afternoon.

In general terms, it looks like very typical weather for late August in the Ohio Valley. However, the development of these clouds is dependent on warming from the afternoon sun, and of course, solar heating will be reduced during Monday afternoon. Cumulus clouds may begin to form and then dissipate as the air cools in response to the eclipse. The same holds true for Tennessee, with 30 to 40 percent cloud cover currently anticipated, with only a slight probability (20 percent or less) for most of this region.

Piedmont and Southeast coast 

Our final stop is northeast Georgia and the Carolinas. Unfortunately, a stalled weather front is running from northern sections of Georgia and South Carolina east through the south end of North Carolina. And that front quite possibly could generate scattered afternoon showers and thunderstorms, which may wreak havoc for those wanting to witness the eclipse.

In this type of summer/sultry pattern, it is always difficult to discern, especially a few days out, specifically the different cloud and precipitation coverage. On a positive note, there are signs that an offshore ridge of high pressure will try to build in, possibly suppressing somewhat any cloud or shower development. The eclipse could also aid in keeping the threat of daytime clouds and shower development down by helping to lower temperatures in similar fashion to what we noted for Kentucky and Tennessee. Still, based on the projected setup, it is prudent to mention at least a 30 to 35 percent chance of showers and thunderstorms. Based on long-term climatological records, the best chance of encountering building afternoon clouds and showers will be over the high-terrain areas (Blue Ridge, Appalachian and Great Smoky mountains), while the best chance of getting some views of the sun will be along the coastal plain.

Some useful websites

Here are some websites related to weather and the upcoming Great American Solar Eclipse that may interest you:

National Weather Service Eclipse Page

Joe Rao's Eclipse Tutorial and Weather Prospects in Weatherwise Magazine

Jay Anderson's Great American Eclipse Weather Page

Joe Rao serves as an instructor and guest lecturer at New York's Hayden Planetarium. He writes about astronomy for Natural History magazine, the Farmer's Almanac and other publications, and he is also an on-camera meteorologist for Fios1 News based in Rye Brook, New York. Follow us @Spacedotcom, Facebook and Google+. Original article on

Cassini-Huygens: Exploring Saturn's System

Cassini-Huygens: Exploring Saturn's System:

Cassini-Huygens: Exploring Saturn's System
Artist's concept of NASA's Cassini spacecraft at Saturn.
Credit: NASA/JPL

The Cassini spacecraft has been orbiting Saturn since 2004. The mission is known for discoveries such as finding jets of water erupting from Enceladus, and tracking down a few new moons for Saturn. Now low on fuel, the spacecraft will make a suicidal plunge into the ringed planet in 2017 and capture some data about Saturn's interior on the way. (This will avoid the possibility of Cassini crashing someday onto a potentially habitable icy moon, such as Enceladus or Rhea.)

The ambitious mission is a joint project among several space agencies, which is a contrast from the large NASA probes of the past such as Pioneer and Voyager. In this case, the main participants are NASA, the European Space Agency and Agenzia Spaziale Italiana (the Italian space agency).

Development history

Cassini is the first dedicated spacecraft to look at Saturn and its system. It was named for Giovanni Cassini, a 17th-century astronomer who was the first to observe four of Saturn's moons — Iapetus (1671), Rhea (1672), Tethys (1684) and Dione (1684).

Before this spacecraft came several flybys of Saturn by Pioneer 11 (1979), Voyager 1 (1980) and Voyager 2 (1981). Some of the discoveries that came out of these missions included finding out that Titan's surface can't be seen in visible wavelengths (due to its thick atmosphere), and spotting several rings of Saturn that were not visible with ground-based telescopes.

It was shortly after the last flyby, in 1982, that scientific committees in both the United States and Europe formed a working group to discuss possible future collaborations. The group suggested a flagship mission that would orbit Saturn, and would send an atmospheric probe into Titan. However, there was a difficult "fiscal climate" in the early 1980s, NASA's Jet Propulsion Laboratory noted in a brief history of the mission, which pushed approval of Cassini to 1989.

The Europeans and the Americans each considered either working together, or working solo. A 1987 report by former astronaut Sally Ride, for example, advocated for a solo mission to Saturn. Called "NASA's Leadership and America's Future in Space," the report said that studying the outer gas giant planets (such as Saturn) help scientists learn about their atmospheres and internal structure. (Today, we also know that this kind of study helps us predict the structure of exoplanets, but the first exoplanets were not discovered until the early 1990s.)

"Titan is an especially interesting target for exploration because the organic chemistry now taking place there provides the only planetary-scale laboratory for studying processes that may have been important in the prebiotic terrestrial atmosphere," the report added, meaning that on Titan is chemistry that could have been similar to what was present on Earth before life arose.

Cassini's development came with at least two major challenges to proceeding. By 1993 and 1994, the mission had a $3.3 billion price tag (roughly $5 billion in 2017 dollars, or about half the cost of the James Webb Space Telescope.) Some critics perceived this as overly high for the mission. In response, NASA pointed out that the European Space Agency was also contributing funds, and added that the technologies from Cassini were helping to fund lower-cost NASA missions such as the Mars Global Surveyor, Mars Pathfinder and the Spitzer Space Telescope, according to JPL.

Cassini also received flak from environmental groups who were concerned that when the spacecraft flew by Earth, its radioisotope thermoelectric generator (nuclear power) could pose a threat to our planet, JPL added. These groups filed a legal challenge in Hawaii shortly before launch in 1997, but the challenge was rejected by the federal district court in Hawaii and the Ninth Circuit Court of Appeals.

To address concerns about the spacecraft's radioisotope thermoelectric generators, which are commonly used for NASA missions, NASA responded by issuing a supplementary document about the flyby and detailing the agency's methodology for protecting the planet, saying there was less than a one-in-a-million chance of an impact occurring.

Saturn's largest moon, Titan, passes in front of the planet and its rings in this true color snapshot from NASA's Cassini spacecraft. This view looks toward the northern, sunlit side of the rings from just above the ring plane. It was taken on May 21, 2011, when Cassini was about 1.4 million miles (2.3 million kilometers) from Titan.
Credit: NASA/JPL-Caltech/Space Science Institute

Launch and cruise

Cassini didn't head straight to Saturn. Rather, its mission involved complicated orbital mechanics. It went past several planets — including Venus (twice), Earth and Jupiter — to get a speed boost by taking advantage of each planet's gravity.

The nearly 12,600-lb. (about 5,700 kilograms) spacecraft was hefted off Earth on Oct. 15, 1997. It went by Venus in April 1998 and June 1999, Earth in August 1999 and Jupiter in December 2000.

Cassini settled into orbit around Saturn on July 1, 2004. Among its prime objectives were to look for more moons, to figure out what caused Saturn's rings and the colors in the rings, and understanding more about the planet's moons.

Perhaps Cassini's most detailed look came after releasing the Huygens lander toward Titan, Saturn's largest moon. The lander was named for Dutch scientist Christiaan Huygens, who in 1654 turned a telescope toward Saturn and observed that its odd blob-like shape — Galileo Galilei had first seen the shape in a telescope and drew it in his notebook as something like ears on the planet — was in fact caused by rings.

The Huygens lander descended through the mysterious haze surrounding the moon and landed on Jan. 14, 2005. It beamed information back to Earth for nearly 2.5 hours during its descent, and then continued to relay what it was seeing from the surface for 1 hour 12 minutes.

In that brief window of time, researchers saw pictures of a rock field and got information back about the moon's wind and gases on the atmosphere and the surface.

This first panorama of Titan released by ESA shows a full 360-degree view around the Huygens probe. The left-hand side shows a boundary between light and dark areas. The white streaks seen near this boundary could be ground 'fog', as they were not immediately visible from higher altitudes. Huygens drifted over a plateau (centre of image) and was heading towards its landing site in a dark area (right) during descent.
Credit: ESA/NASA/University of Arizona.

Magnificent moons

One of the defining features of Saturn is its number of moons. Excluding the trillions of tons of little rocks that make up its rings, Saturn has 62 discovered moons as of September 2012. NASA lists 53 named moons on one of its websites.

In fact, Cassini discovered two new moons almost immediately after arriving (Methone and Pallene) and before 2004 had ended, it detected Polydeuces. [Gallery: Latest Saturn Photos from NASA's Cassini Orbiter]

As the probe wandered past Saturn's moons, the findings it brought back to Earth revealed new things about their environments and appearances. Some of the more notable findings include:

Saturn has not gone ignored, either. For example, in 2012, a NASA study postulated that Saturn's jet streams in the atmosphere may be powered by internal heat, instead of energy from the sun. Scientists believe that heat brings up water vapor from the inside of the planet, which condenses as it rises and produces heat. That heat is believed to be behind jet stream formation, as well as that of storms.

Mission extension and end

Cassini was originally slated to last four years at Saturn, until 2008, but its mission has been extended multiple times. Its last and final leg was called the Cassini Solstice Mission, named because the planet and its moons reached the solstice again toward the mission end. Saturn orbits the sun every 29 Earth-years. With Cassini's mission lasting 13 years, this meant that the spacecraft observed almost half of Saturn's seasonal change as the planet went around its orbit.

In 2016, the spacecraft was set on a series of final maneuvers to provide close-up views of the rings, with the ultimate goal of plunging Cassini into Saturn on Sept. 15, 2017. This protected Enceladus and other potentially habitable moons from the (small) chance of Cassini colliding with the surface, spreading Earth microbe.

Major milestones of the finale included:

  • Ring-grazing orbits: Every week between Nov. 30, 2016, and April 22, 2017, Cassini did loops around Saturn's poles to look at the outer edge of the rings, to learn more about their particles, gases and structure. It also observed small moons in this region, including Atlas, Daphnis, Pan and Pandora.
  • On April 22, 2017, Cassini made the final flyby of Titan. The flyby was done in such a way to change Cassini's orbit so that it began 22 dives (once a week) between the planet and its rings. This was the first time any spacecraft explored this zone, and it entailed some risk because the orbit brought it between the outer part of the atmosphere and the inner zone of the rings (where it is at risk of striking particles or gas molecules). 
  • On Sept. 15, 2017, Cassini will make a suicidal plunge into Saturn, taking measurements for as long as its instruments can make communications back to Earth.
Some of the science Cassini performed during this period included creating maps of the planet's gravity and magnetic fields, estimating how much material is in the rings, and taking high-resolution images of Saturn and its rings from close-up.

The spacecraft made an interesting discovery from its new vantage point. It found that Saturn's magnetic field is closely aligned with the planet's axis of rotation, which baffled scientists because of how they think magnetic fields are generated — through a difference of tilt between the magnetic field and a planet's rotation. As of late July 2017, however, scientists planned to gather more data to see if perhaps Saturn's internal processes confused their measurements.

Additional resource

How Astronomers Use Eclipses to Discover Alien Worlds

How Astronomers Use Eclipses to Discover Alien Worlds:

How Astronomers Use Eclipses to Discover Alien Worlds
Artist's illustration of the star system Kepler-444, whose five planets were discovered by the Kepler space telescope as they passed in front of their star, dimming its light. All five orbit the star within less than 10 days.
Credit: Tiago Campante/Peter Devine

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 Sutter contributed this article to's Expert Voices: Op-Ed & Insights.

As we prepare for the upcoming total solar eclipse set to cross the continental United States on Aug. 21, the mechanics of the event are pretty straightforward to explain: Occasionally the sun, moon and Earth end up in straight line, and when they do, the moon casts its shadow on the Earth. Voila: eclipse!

From our perspective here on the surface of the Earth, it appears as if the disk of the moon covers the face of the sun. You have to be near or at totality — when the sun is fully covered — to notice the sun's dimming with your unaided eyes. However, sophisticated light-measuring instruments can easily pick up even the slightest hint of reduction in sunlight no matter the extent of the eclipse.

Now let's play a game. Let's say you attached these keen instruments to a telescope and you rocketed a few light-years away from the solar system. And instead of observing the sun-moon eclipse, you stared at the sun as the Earth meandered in its orbit. If you lined everything up just right and stared long enough, eventually you would get to see the tiny planet cross the face of its massive sun. [Total Solar Eclipse 2017: Here Are the Best Live-Video Streams to Watch]

With enough dedication to your astronomical duties, you could conceivably measure a dip in brightness as the Earth entered the edge of the sun, and a return to normalcy as the planet moved on.

Let's take it to the extreme: You're so far away that you can't even see a tiny dot representing the Earth. Could you still measure the telltale dip in brightness? Well, measuring the light output of a star is much easier than hunting for an insignificant speck of a rocky world, so I suppose with enough technological progress one could achieve it.

And imagine this: What if we did this all the time? Well, we do. This hunting for subtle eclipses is our primary method for detecting exoplanets — planets outside the solar system, orbiting their own host stars. Of course, astronomers don't call it "subtle eclipse method," but rather the "transit method."

This method allows us to find exoplanets big and small orbiting stars of all sizes and ages. Over 4,000 planets and counting! We haven't found an exact match for Earth yet — but we're getting closer to finding a match with every new planet detected.

The transit method isn't perfect, of course; it relies on a chance alignment among the star, the exoplanet and us. If that planet just happens to orbit perpendicular to our line of sight, we're out of luck. Thankfully, there are, to put it mildly, many stars out there, even within our nearby galactic neighborhood, so enough coincidences occur to give us a solid census of our celestial cousins.

So, as you're feasting your eyes on the upcoming solar eclipse, you might wonder if some distant observer is also enjoying the event.

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

Here's What It's Like to Be the Planetary Protection Officer at NASA

Here's What It's Like to Be the Planetary Protection Officer at NASA:

Here's What It's Like to Be the Planetary Protection Officer at NASA
Credit: Reid Wiseman/NASA

If you want a job protecting Earth from threats from outer space — or even protecting Mars from us — NASA has an opening for you — sort of. The job of planetary protection officer generated quite a bit of buzz last week, when the public learned that a role seemingly out of a science fiction novel was actually a bonafide NASA job. But the position has nothing to do with protecting Earth from little green men, but a whole lot to do with important interplanetary science.

A primary task of the officer is to make sure that during NASA missions earthly microbes don't contaminate potentially habitable environments. And should a mission bring back samples from outer space, the officer is tasked with making sure that dust, or rocks, or whatever is brought back from outer space doesn't contaminate us.

John Rummel, a biology professor at East Carolina University, held the position twice, first between 1990 and 1993 and again from 1998 to 2006.

"The planetary protection job was mostly challenging in that it was not just important for each mission to do the right — required by requirements — thing, but to know why they were doing it, and why it was important to do a good job," Rummel said. "From that aspect, the job was definitely worth it. But as to 'rewards,' those were mostly internal.”

Rummel explained that the planetary protection office reports to the associate administrator for each mission, who oversees the cost of the project. That means recommendations made by the officer are often judged in the context of whether or not they will cost the administrator more money — a vexing problem many of us might easily understand from our own work experiences.

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

Rummel's time as planetary protection officer coincided with the restart of NASA's Mars program.

After the successful twin Viking landings of the 1970s, a few famous searching-for-life experiments came up empty. NASA shifted its attention to other locations in the solar system, and Mars didn't get a launch opportunity until the failed Mars Observer mission in 1992.

A slew of missions followed, however, including the Mars Pathfinder mission that made it all the way to the surface in 1996 and deployed a mini-rover – Sojourner. Several other landing and orbiting missions followed — some successful, others not.

Those missions wouldn't have been possible without the approval of the planetary protection officer, who ensured that Sojourner and other Martian spacecraft were sterile enough to prevent microbes from taking root in potentially life-friendly areas. One of Rummel's first tasks in 1990 was to look at the risk of contamination on Mars and how scientific understanding had changed since the days of the Viking missions.

"I knew people would like to go back and land on Mars, but I also knew we didn't have current advice," Rummel said.

So he assisted in the drafting of a 1992 report – Biological Contamination of Mars. The report concluded that a large part of the surface was "extremely inhospitable to terrestrial life" and for that reason, future missions would not need to be sterilized as much as the Viking missions.

But changes in landing technology meant that NASA had to be extra mindful of different scenarios for its missions. Pathfinder, for example, was supposed to fall to the surface using airbags. If the airbags failed, the mission would need to withstand a fall and possible burial in the soil of up to 1.5 meters (5 feet) without exposing possible Earth microbes to the Martian environment.

NASA has seen extensive evidence of briny water flow in recurring slope lineae, which are features that develop on the slopes of craters. Rummel, among others, speculated about recurring slope lineae as early as 2002. While researchers have long observed the formations, it was only in 2015 that NASA had strong enough evidence to say the formations are probably due to liquid water on the surface.

Rummel warned against sending Curiosity to investigate a nearby recurring slope lineae. The materials on the rover's surface could not be thoroughly sterilized with UV radiation due to their properties. And inside the rover is a warm electronics box that could melt any ice with which the box comes into contact.

RELATED: NASA Center Shows Off Sleek New Mars Rover Concept Vehicle for Astronauts

Rummel was also part of early-stage planning for a "sample return" mission to bring pieces of Mars back to Earth, in collaboration with the French space agency CNES. While that mission never went forward, NASA has left the door open for future sample return missions. The next Mars rover, called Mars 2020, is expected to leave "caches" of interesting material behind for future missions to potentially pick up and bring back to Earth, when we presumably know a little more about how to protect ourselves.

Of course, Mars wasn't the only target of note back in the 1990s when Rummel began his work. NASA already had a Jupiter probe — called Galileo — and was about to launch Cassini, which has now been orbiting Saturn since 2004. Those missions confirmed some intriguing Voyager mission results from the 1970s and 1980s, showing that some of the moons are icy and potentially habitable.

Rummel remembers modifying the planetary protection plan for Galileo as evidence emerged that a liquid ocean might lie underneath Europa's icy surface.

At the end of Galileo's mission, an option was included to deliberately crash the probe into Io or Jupiter, just in case it happened to fall into Europa, damaging a potentially habitable environment underneath the ice. Because the mission planners were uncomfortable with changing Galileo's orbit to fall into Io, they went for a Jupiter extermination — collecting science all the way down.

NASA said the job posting has generated "a lot of excitement," including from Jack Davis a fourth grader from New Jersey and self-described "Guardian of the Galaxy." In a letter to the agency, Davis said he was fit for the job because his sister thought he was an alien, among other qualifications.

Although the planetary protection officer is no intergalactic warrior, it's a position that clearly provokes the imagination of skywatchers young and old.

Originally published on Seeker.

How to View a Solar Eclipse Without Damaging Your Eyes

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 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

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 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

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.

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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:

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. 

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. recently caught up with Stone, who talked about the 40-year anniversary, Voyager's greatest accomplishments and the mission's legacy. 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. 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. 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. 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. 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. 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, 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. 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

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

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

 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 for a live solar eclipse webcast Monday, courtesy of NASA, beginning at 12 p.m. EDT (1600 GMT).

Follow Paul @PaulMattSutter and us @Spacedotcom, Facebook and Google+. Original article on

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: 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
See Explanation. Clicking on the picture will download the highest resolution version available.
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

See Explanation. Clicking on the picture will download the highest resolution version available.
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

See Explanation. Clicking on the picture will download the highest resolution version available.

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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Thursday, August 17, 2017

Why the Total Solar Eclipse Arrives from the West

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.

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

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.

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