EAGLE NEBULA - Messier 16 (M16) – The Eagle Nebula

Messier 16 (M16) – The Eagle Nebula:

Welcome back to Messier Monday! In our ongoing tribute to the great Tammy Plotner, we take a look at the Messier 16 open star cluster - aka. The Eagle Nebula (and a slew of other names). Enjoy!



In the 18th century, while searching the night sky for comets, French astronomer Charles Messier began noticing a series of “nebulous objects” in the night sky. Hoping to ensure that other astronomers did not make the same mistake, he began compiling a list of these objects,. Known to posterity as the Messier Catalog, this list has come to be one of the most important milestones in the research of Deep Sky objects.



One of these objects it he Eagle Nebula (aka. NGC 661. The Star Queen Nebula and The Spire), a young open cluster of stars located in the Serpens constellation. The names "Eagle" and "Star Queen" refer to visual impressions of the dark silhouette near the center of the nebula. The nebula contains several active star-forming gas and dust regions, which includes the now-famous "Pillars of Creation".

Description:

Located some 7,000 light years away in the next inner spiral arm of the Milky Way galaxy, the Eagle Nebula spans some 70 by 50 light years across. Born around 5.5 million years ago, this glittering swarm marks an area about 15 light years wide, and within the heart of this nebula is a cluster of stars and a region that has captured our imaginations like nothing else - the "Pillars of Creation".



Here, star formation is going on. The dust clouds are illuminated by emission light, where high-energy radiation from its massive and hot young stars excited the particles of gas and makes them glow. Inside the pillars are Evaporating Gaseous Globules (EGGs), concentrations of gas that are emerging from the "womb" that about to become stars.







These pockets of interstellar gas are dense enough to collapse under their own weight, forming young stars that continue to grow as they accumulate more and more mass from their surroundings. As their place of birth contracts gravitationally, the interior gas reaches its end and the intense radiation of bright young stars causes low density material to boil away.



These regions were first photographed by the Hubble Space Telescope in 1995. As Jeff Hester - a professor at Arizona State University and an investigator with the Hubble's Wide Field and Planetary Camera 2 (WFPC2) - said of the discovery:

"For a long time astronomers have speculated about what processes control the sizes of stars - about why stars are the sizes that they are. Now in M16 we seem to be watching at least one such process at work right in front of our eyes."

The Hubble has shown us what happens when all the gas boils away and only the EGGs are left. "It's a bit like a wind storm in the desert," said Hester. "As the wind blows away the lighter sand, heavier rocks buried in the sand are uncovered. But in M16, instead of rocks, the ultraviolet light is uncovering the denser egg-like globules of gas that surround stars that were forming inside the gigantic gas columns."







And some of these EGGs are nothing more than what would appear to be tiny bumps and teardrops in space - but at least we are looking back in time to see what stars look like when they were first born. "This is the first time that we have actually seen the process of forming stars being uncovered by photoevaporation," Hester emphasized. "In some ways it seems more like archaeology than astronomy. The ultraviolet light from nearby stars does the digging for us, and we study what is unearthed."

History of Observation:

The star cluster associated with M16 (NGC 6611) was first discovered by Philippe Loys de Chéseaux in 1745-6. However, it was Charles Messier who was the very first to see the nebulosity associated with it. As he recorded in his notes:

"In the same night of June 3 to 4, 1764, I have discovered a cluster of small stars, mixed with a faint light, near the tail of Serpens, at little distance from the parallel of the star Zeta of that constellation: this cluster may have 8 minutes of arc in extension: with a weak refractor, these stars appear in the form of a nebula; but when employing a good instrument one distinguishes these stars, and one remarks in addition a nebulosity which contains three of these stars. I have determined the position of the middle of this cluster; its right ascension was 271d 15' 3", and its declination 13d 51' 44" south."

Oddly enough, Sir William Herschel, who was famous for elaborating on Messier's observations, didn't seem to notice the nebula at all (according to his notes). And Admiral Smyth, who could always be counted on for flowery prose about stellar objects, just barely saw it as well:

"A scattered but fine large stellar cluster, on the nombril of Sobieski's shield, in the Galaxy, discovered by Messier in 1764, and registered as a mass of small stars in the midst of a faint light. As the stars are disposed in numerous pairs among the evanescent points of more minute components, it forms a very pretty object in a telescope of tolerable capacity."

But of course, the nebula isn't an easy object to spot and its visibility on any given night depends greatly on sky conditions. As historical evidence suggest, only one of the two masters (Messier) caught it. So take a lesson from history and return to the sky many times. One day you'll be rewarded!

Locating Messier 16:

One of the easiest ways to find M16 is to identify the constellation of Aquila and begin tracing the stars down the eagle's back to Lambda. When you reach that point, continue to extend the line through to Alpha Scuti, then southwards towards Gamma Scuti. Aim your binoculars or image correct finderscope at Gamma and put it in the 7:00 position.







For those using a finderscope, M16 will easily show up as a faint haze. Even those using binoculars won't miss it. If Gamma is in the lower left hand corner of your vision - then M16 is in the upper right hand. For all optics, you won't be able to miss the open star cluster and the faint nebulosity of IC 4703 can be seen from dark sky locations.



Another way to find M16 is by first locating the "Teapot" asterism in Sagittarius constellation (see above), and then by following the line from the star Kaus Australis (Epsilon Sagittarii) - the brightest star in Sagittarius - to just east of Kaus Media (Delta Sagittarii). Another way to find the nebula is by extending a line from Lambda Scuti in Scutum constellation to Alpha Scuti, and then to the south to Gamma Scuti.



Those using large aperture telescopes will be able to see the nebula well, but sky conditions are everything when it comes to this one. The star cluster which is truly M16 will always be easy, but the nebula is a challenge.



And as always, here are the quick facts on M16 to help you get started:



Object Name: Messier 16

Alternative Designations: M16, NGC 6611, Eagle Nebula (IC 4703)

Object Type: Open Star Cluster and Emission Nebula

Constellation: Serpens (Cauda)

Right Ascension: 18 : 18.8 (h:m)

Declination: -13 : 47 (deg:m)

Distance: 7.0 (kly)

Visual Brightness: 6.4 (mag)

Apparent Dimension: 7.0 (arc min)



And be sure to enjoy this video of the Eagle Nebula and the amazing photographs of the "Pillar of Creation":



https://youtu.be/fNeM3S6b1Ts



We have written many interesting articles about Messier Objects here at Universe Today. Here’s Tammy Plotner’s Introduction to the Messier Objects, , M1 – The Crab Nebula, M8 – The Lagoon Nebula, and David Dickison’s articles on the 2013 and 2014 Messier Marathons.



Be to sure to check out our complete Messier Catalog. And for more information, check out the SEDS Messier Database.

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IMAGES OF JUPITER - Very Large Telescope Images Of Jupiter Prepare Us For Juno Arrival

Very Large Telescope Images Of Jupiter Prepare Us For Juno Arrival:

Launching back in 2011, NASA's Juno mission has spent the past five years traversing the gulf that lies between Earth and Jupiter. When it arrives (in just a few days time!), it will be the second long-term mission to the gas giant in history. And in the process, it will obtain information about its composition, weather patterns, magnetic and gravitational fields, and history of formation.



With just days to go before this historic rendezvous takes place, the European Southern Observatory is taking the opportunity to release some spectacular infrared images of Jupiter. Taken with the Very Large Telescope (VLT), these images are part of a campaign to create high-resolutions maps of the planet, and provide a preview of the work that Juno will be doing in the coming months.



Using the VTL Imager and Spectrometer for mid-Infrared (VISIR) instrument, the ESO team - led by Dr. Leigh Fletcher of the University of Leicester - hopes that their efforts to map the planet will improve our understanding of Jupiter's atmosphere. Naturally, with the upcoming arrival of Juno, some may wonder if these efforts are necessary.







After all, ground-based telescopes like the VLT are forced to contend with limitations that space-based probes are not. These include interference from our constantly-shifting atmosphere, not to mention the distances between Earth and the object in question. But in truth, the Juno mission and ground-based campaigns like these are often highly complimentary.



For one, in the past few months, while Juno was nearing in on its destination, Jupiter's atmosphere has undergone some significant shifts. Mapping these is important to Juno's upcoming arrival, at which point it will be attempting to peer beneath Jupiter's thick clouds to discern what is going on beneath. In short, the more we know about Jupiter's shifting atmosphere, the easier it will be to interpret the Juno data.



As Dr. Fletcher described the significance of his team's efforts:

“These maps will help set the scene for what Juno will witness in the coming months. Observations at different wavelengths across the infrared spectrum allow us to piece together a three-dimensional picture of how energy and material are transported upwards through the atmosphere.”

Like all ground-based efforts, the ESO campaign - which has involved the use of several telescopes based in Hawaii and Chile, as well as contributions from amateur astronomers around the world - faced some serious challenges (like the aforementioned interference). However, the team used a technique known as "lucky imaging" to take the breathtaking snapshots of Jupiter's turbulent atmosphere.

What this comes down to is taking many sequences of images with very short exposures, thus producing thousands of individual frames. The lucky frames, those where the image are least affected by the atmosphere’s turbulence, are then selected while the rest discarded. These selected frames are aligned and combined to produce final pictures, like the one shown above.

In addition to providing information that would be of use to the Juno mission, the ESO's campaign has value that extends beyond the space-based mission. As Glenn Orton, the leader of ESO's ground-based campaign, explained, observations like these are valuable because they help to advance our understanding of planets as a whole, and provide opportunities for astronomers from all over the world to collaborate.



“The combined efforts of an international team of amateur and professional astronomers have provided us with an incredibly rich dataset over the past eight months," he said. "Together with the new results from Juno, the VISIR dataset in particular will allow researchers to characterize Jupiter’s global thermal structure, cloud cover and distribution of gaseous species.”



The Juno probe will be arriving at Jupiter this coming Monday, July 4th. Once there, it will spend the next two years orbiting the gas giant, sending information back to Earth that will help to advance our understanding of not only Jupiter, but the history of the Solar System as well.



Further Reading: ESO

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Behold The Distant Universe!

Behold The Distant Universe!:

This past Monday (June 27th), the National Astronomy Meeting - which is hosted by the Royal Astronomy Society - kicked off at the University of Nottingham in the UK. As one of the largest professional conferences in Europe (with over 500 scientists in attendance), this annual meeting is an opportunity for astronomers and scientists from a variety of fields to present that latest in their research.



And of the many presentations made so far, one of the most exciting came from a research team from the University of Nottingham's School of Physics and Astronomy, which presented the latest near-infrared images obtained by the Ultra Deep Survey (UDS). In addition to being a spectacular series of pictures, they also happened to be the deepest view of the Universe to date.



The UDS survey, which began in 2005, is one of the five projects that make up the UKIRT's Infrared Deep Sky Survey (UKIDSS). For the sake of their survey, the UDS team relies on the Wide Field Camera (WFCAM) on the United Kingdom Infrared Telescope in Mauna Kea, Hawaii. At 3.8-metres in diameter, the UKIRT is the world’s second largest telescope dedicated to infrared astronomy.



As Professor Omar Almaini, the head of the University of Nottingham research team, explained to Universe Today via email:

"The UDS is by far the deepest near-infrared survey over such a large, contiguous area (0.8 sq degrees). There is only one other similar survey, which is known as UltraVISTA. It covers a larger area (1.5 sq degree) but is not quite so deep. Together the UDS and UltraVISTA should revolutionize studies of the high-redshift Universe over the next few years."

Ultimately, the goal of UDS is shed light on how and when galaxies form, and to chart their evolution over the course of the last 13 billion years (roughly 820 million years after the Big Bang). For over a decade, the UDS has been observing the same patch of sky repeatedly, relying on optical and infrared imaging to ensure that the light of distant objects (which is redshifted due to the profound distances involved) can be captured.



"Stars emit most of their radiation at optical wavelengths, which is redshifted to the near-infrared at high redshift," said Almaini. "Near-infrared surveys therefore provide the least biased census of galaxies in the early Universe and the best measurements of the stellar mass. Deep optical surveys will only detect galaxies that are bright in the rest-frame ultraviolet, so they are biased against galaxies that are obscured by dust, or those that have stopped forming stars."



In total, the project has accumulated more than 1000 hours of exposure time, detecting over two hundred and fifty thousand galaxies - several hundred of which were observed within the first billion years after the Big Bang. The final images, which were released yesterday and presented at the National Astronomy Meeting, showed an area four times the size of the full Moon, and at an unprecedented depth.



Data previously released by the UDS project has already led to several scientific advances. These include studies of the earliest galaxies in the Universe after the Big Bang, measurements on the build-up of galaxies over time, and studies of the large-scale distribution of galaxies to measure the influence of dark matter.







With this latest release, many more are anticipated, with astronomers around the world spending the next few years studying the early stages of galaxy formation and evolution. As Almaini put it:

"With the UDS (and UltraVISTA) we now have the ability to study large samples of galaxies in the distant Universe, rather than just a handful. With thousands of galaxies at each epoch we can perform detailed comparisons of the evolving galaxy populations, and we can also study their large-scale structure to understand how they trace the underlying cosmic web of dark matter. With large samples we can also look for rare but important populations, such as those in transition."



"A key aim is to understand why many massive galaxies abruptly stop forming stars around 10 billion years ago, and also how they transform from disk-like systems into elliptical galaxies. We have recently identified a few hundred examples of galaxies in the process of transformation at early times, which we are actively studying to understand what is driving the rapid changes."

Along with the subject of galaxy surveys and large scale structure, "galaxy formation and evolution" and "galaxy surveys and large scale structure" were two of the 2016 National Astronomy Meeting's main themes. Naturally, the UDS release fit neatly into both categories. The others themes included the Sun, stars and planetary science, gravitational waves, modified gravity, archeoastronomy, astrochemistry, and education and outreach.



The Meeting will run until tomorrow (Friday, July 1st), and also included a presentations on the latest infrared images of Jupiter, which were taken by the ESO in preparation for the Juno spacecraft's arrival on July 4th.



Further Reading: Royal Astronomical Society

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JUPITER PLANET - Jupiter’s Magnetosphere Will Blow Your Mind While it Kills Your Spacecraft

Jupiter’s Magnetosphere Will Blow Your Mind While it Kills Your Spacecraft:

Jupiter is a huge planet, but its magnetosphere is mind-blowingly massive. It extends out to nearly 5 million kilometers (3 million miles) wide on average, 150 times wider than Jupiter itself and almost 15 times wider than the Sun, making it one of the largest structures in the Solar System.



“If you were to look up into the night sky and if we could see the outline of Jupiter’s magnetosphere, it would be about the size of the Moon in our sky,” said Jack Connerney, deputy principal investigator and head of the Juno mission magnetometer team. “It’s a very large feature in our Solar System, and it’s a pity we can’t see it.”



But the Juno spacecraft is about to change our understanding of Jupiter’s magnetosphere and allow scientists to “see” for the first time Jupiter’s magnetic field.



And today, NASA announced that Juno has entered Jupiter's magnetic field. Listen to the video below as the spacecraft gathered data as it crossed the bow shock:





A magnetosphere is the area of space around a planet that is controlled by the planet's magnetic field. The stronger the magnetic field, the larger the magnetosphere. It is estimated that Jupiter’s magnetic field is about 20,000 times stronger than Earth's.







Magnetic fields are produced by what are known as dynamos – an electric current created from the convection motion of a planet’s interior. Earth’s magnetic field is generated by its circulating core of molten iron and nickel. But what creates Jupiter’s dynamo? Is it like Earth’s or could it be very different? Jupiter consists predominantly of hydrogen and helium, and it is currently unknown if there is a rocky core at the center of the planet.



"With Jupiter, we don't know what material is producing the planet's magnetic field," said Jared Espley, Juno program scientist for NASA Headquarters, "What material is present and how deep down it lies is one of the questions Juno is designed to answer."



Juno has a pair of magnetometers to basically look inside the planet. The magnetometers will allow scientists to map Jupiter's magnetic field with high accuracy and observe variations in the field over time. The instruments will be able to show how the magnetic field is generated by dynamo action deep in the planet’s interior, providing the first look at what the magnetic field looks like from the surface of the dynamo where it is generated.



"The best way to think of a magnetometer is like a compass," said Connerney. "Compasses record the direction of a magnetic field. But magnetometers expand on that capability and record both the direction and magnitude of the magnetic field."



But Jupiter presents a lot of problems as far as being nice to instruments. Trapped within the magnetosphere are charged particles from the Sun that form intense radiation belts around the planet. These belts are similar to the Earth's Van Allen belts, but are many millions of times stronger.



To help protect the spacecraft and instrument electronics, Juno has a radiation vault about the size of a car trunk made of titanium that limits the radiation exposure to Juno's command and data handling box (the spacecraft's brain), power and data distribution unit (its heart) and about 20 other electronic assemblies. But the instruments themselves need to be outside of the vault in order to make their observations.





The magnetometer sensors are on a boom attached to one of the solar arrays, placing them about 40 feet (12 meters) from the body of the spacecraft. This helps ensure that the rest of the spacecraft does not interfere with the magnetometer.

But there are other ways to help limit the amount of radiation exposure, at least in the first part of the mission.



Scientists designed a path that takes Juno around Jupiter's poles so that the spacecraft spends the least amount of time possible in those blistering radiation belts around Jupiter's equator. Engineers also used designs for electronics already approved for the Martian radiation environment, which is harsher than Earth's, though not as harsh as Jupiter's.



That elliptical orbit -- between radiation belt and the planet --- also puts the spacecraft very close to Jupiter, about 5,000 km above the cloud tops, enabling a close-up look at this amazing planet.



"This is our first opportunity to do very precise, high-accuracy mapping of the magnetic field of another planet," Connerney said. "We are going to be able to explore the entire three-dimensional space around Jupiter, wrapping Jupiter in a dense net of magnetic field observations completely covering the sphere."



By studying Jupiter's magnetosphere, scientists will gain a better understanding about how Jupiter's magnetic field is generated. They also hope to measure how fast Jupiter is spinning, determine whether the planet has a solid core, and learn more about Jupiter’s formation.



“It’s always incredible to be the first person in the world to see anything,” Connerney said, “and we stand to be the first to look down upon the dynamo and see it clearly for the first time.”







Further reading: Juno mission page, NASA article on Juno's magnetometer.

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MORE 5 PLANETS - New System Discovered with Five Planets

New System Discovered with Five Planets:

NASA's planet-discovering Kepler mission suffered a major mechanical failure in May 2013, but thanks to innovative techniques subsequently implemented by astronomers the satellite continues to uncover worlds beyond our Solar System (i.e., exoplanets).  Indeed, Andrew Vanderburg (CfA) and colleagues just published results highlighting a new system found to host five transiting planets, which include: two sub-Neptune sized planets, a Neptune sized planet, a sub-Saturn sized planet, and a Jupiter sized planet.







The team was able to identify the rare suite of five planets in Kepler's extended mission data by developing algorithms that attempt to compensate for the satellite's instability, which resulted from the mechanical failure that occurred in 2013.  A member on the team, Martti H. Kristiansen, identified the five transits in diagrams subsequently produced by their pipeline.  The image below conveys the raw and corrected data, whereupon bona fide transits are readily discernible in the latter.



Vanderburg and colleagues obtained spectra that implies the star hosting the planets (designated HIP 41378) is relatively similar to the Sun, featuring a radius and mass of 1.4 and 1.15 times that of the Sun, respectively.  However, the planets in the newly discovered system were found to complete their orbits in a comparatively short time (typically less than 1 year).    The shorter orbital periods are often a result of a selection bias that stems from efforts aimed at detecting planetary systems using the transit method, which uncovers planets by identifying the drop in brightness that occurs as an exoplanet passes in front of its host star along our sight-line.  Such transits are rare because of the impracticality of monitoring a target host star unceasingly, and because of orientation effects (i.e., a near edge-on perspective is required).   The Kepler satellite monitored HIP 41378 for 75 days.







The original Kepler mission observed a 110 square degree field for four years, and Vanderburg noted Kepler's extended (K2) mission could survey an area up to 20 times larger, thus significantly increasing the number of objects observed.  In particular, it is hoped that a suite of new exoplanets could be discovered orbiting brighter host stars, as those identified during the original Kepler mission were typically faint.  Precise velocity measurements are difficult to achieve for fainter stars, and the data are needed to complement brightness measurements and further characterize the exoplanets discovered.  Specifically, results inferred from the transit search method are often paired with those determined from velocity (Doppler) analyses to yield the density of the planetary systems (e.g., is it a water world?).   Vanderburg noted that the system they discovered possesses amongst the brightest planet host stars from either the Kepler or K2 missions, and is an ideal target for future velocity observations, "it could therefore be detectable with spectrographs like HARPS-N and HIRES in the northern hemisphere, and HARPS and PFS in the south."



The Kepler satellite provides an advantageously large field of view, to enable the simultaneous monitoring of numerous targets, yet a disadvantage is that its resolution is rather coarse.  Indeed, the comparatively poor resolution can result in spurious transit signals ("planet impostors"), which are actually binary star systems in disguise.  “There are many things in the sky that can produce transit-like signals that are not planets, and thus we must be sure to identify what really is a planet detected by Kepler,” Stephen Bryson told Universe Today in 2013.  A pseudo planetary transit could occur owing to a chance superposition of a bright star and a fainter eclipsing binary system, whereby the objects lie at different distances along the sight-line.  The bright foreground star dilutes the typically large eclipses produced by the binary system, hence mimicking the smaller eclipses displayed by transiting planets.   Vanderburg and colleagues evaluated that possibility by obtaining higher-resolution images using the Robo-AO adaptive optics system on the 2.1-m telescope at the Kitt Peak National Observatory.  The adaptive optics system helps correct distortions imposed by Earth's atmosphere, thus yielding an admirably high-resolution image that did not appear to feature contaminating stars.







Vanderburg noted optimistically that, "Discoveries such as the HIP 41378 system show the value of wide-field space-based transit surveys. The Kepler spacecraft had to search almost 800 square degrees of sky (or seven fields of view) before finding such a bright multi-planet system suitable for follow-up observations. HIP 41378 is a preview of the type of discoveries the TESS satellite (2017 launch date) will make routine."



The Vanderburg et al. 2016 study has been accepted for publication in the Astrophysical Journal Letters, and a preprint is available on arXiv.  The coauthors on the study are Juliette C. Becker, Martti H. Kristiansen, Allyson Bieryla, Dmitry A. Duev, Rebecca Jensen-Clem, Timothy D. Morton, David W. Latham, Fred C. Adams, Christoph Baranec, Perry Berlind, Michael L. Calkins, Gilbert A. Esquerdo, Shrinivas Kulkarni, Nicholas M. Law, Reed Riddle, Maissa Salama, and Allan R. Schmitt.  If you’d like to help the Kepler team identify planets around other stars: join the Planet Hunters citizen science project.

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GENERAL RELATIVITY - What is Time Dilation?

What is Time Dilation?:





One of the most interesting topics in the field of science is the concept of General Relativity. You know, this idea that strange things happen as you near the speed of light. There are strange changes to the length of things, bizarre shifting of wavelengths. And most puzzling of all, there’s the concept of dilation: how you can literally experience more or less time based on how fast you’re traveling compared to someone else.

And even stranger than that? As we saw in the movie Interstellar, just spending time near a very massive object, like a black hole, can cause these same relativistic effects. Because mass and acceleration are sort of the same thing?

Honestly, it’s enough to give you a massive headache.

But just because I find the concept baffling, I’m still going to keep chipping away, trying to understand more about it and help you wrap your brain around it too. For my own benefit, for your benefit, but mostly for my benefit.

There’s a great anecdote in the history of physics – it’s probably not what actually happened, but I still love it.

One of the most famous astronomers of the 20th century was Sir Arthur Eddington, played by a dashing David Tennant in the 2008 movie, Einstein and Eddington. Which, you should really see, if you haven’t already.

So anyway, Doctor Who, I mean Eddington, had worked out how stars generate energy (through fusion) and personally confirmed that Einstein’s predictions of General Relativity were correct when he observed a total Solar Eclipse in 1919.

Arthur Eddington

Apparently during a lecture by Sir Arthur Eddington, someone asked, “Professor Eddington, you must be one of the three people in the world who understands General Relativity.” He paused for a moment, and then said, “yes, but I’m trying to think of who the third person is.”

It’s definitely not me, but I know someone who does have a handle on General Relativity, and that’s Dr. Brian Koberlein, an astrophysics professor at the Rochester Institute of Technology. He covers this topic all the time on his blog, One Universe At A Time, which you should totally visit and read at briankoberlein.com.

In fact, just to demonstrate how this works, Brian has conveniently pushed his RIT office to nearly light speed, and is hurtling towards us right now.

---

Dr. Brian Koberlein:

Hi Fraser, thanks for having me. If you can hang on one second, I just have to slow down.

Fraser Cain:

What just happened there? Why were you all slowed down?

Brian:

It’s actually an interesting effect known as time dilation. One of the things about light is that no matter what frame of reference you’re in, no matter how you’re moving through the Universe, you’ll always measure the speed of light in a vacuum to be the same. About 300,000 kilometres per second.

And in order to do that, if you are moving relative to me, or if I’m moving relative to you, our references for time and space have to shift to keep the speed of light constant. As I move faster away from you, my time according to you has to appear to slow down. On the same hand, your time will appear to slow down relative to me.

And that time dilation effect is necessary to keep the speed of light constant.

Fraser:

Does this only happen when you’re moving?

A representation of the coordinate system of the warped space around Earth. Credit: NASA

Brian:

Time dilation doesn’t just occur because of relative motion, it can also occur because of gravity. Einstein’s theory of relativity says that gravity is a property of the warping of space and time. So when you have a mass like Earth, it actually warps space and time.

If you’re standing on the Earth, your time appears to move a little bit more slowly than someone up in space, because of the difference in gravity.

Now, for Earth, that doesn’t really matter that much, but for something like a black hole, it could matter a great deal. As you get closer and closer to a black hole, your time will appear to slow down more and more and more.

Fraser:

What would this mean for space travel?

Brian:

In many times in science fiction, you’ll see the idea of a rocket moving very close to the speed of light, and using time dilation to travel to distant stars.

But you could actually do the same thing with gravity. If you had a black hole that was going out to another star or another galaxy, you could actually take your spaceship and orbit it very close to the black hole. And your time would seem to slow down. While you’re orbiting the black hole, the black hole would take its time to get to another star or another galaxy, and for you it would seem really quick.

Orbiting near a moving black hole doesn’t seem like the safest mode of transportation, but time dilation might make it worth the risk. Credit: NAOJ

So that’s another way that you could use time dilation to travel to the stars, at least in science fiction.

Fraser:

All right Brian, I’ve got one final question for you. If you get more massive as you get closer to the speed of light, could you get so much mass that you turn into a black hole? I’d like you to answer this question in the form of a blog post on briankoberlein.com and on the Google+ post we’re going to link right here.

Brian:

Thanks Fraser, I’ll have that answer up on my website.

---

Once again, we visited the baffling realm of time dilation, and returned relatively unscathed. It doesn’t mean that I understand it any better, but I hope you do, anyway. Once again, a big thanks to Dr. Koberlein for taking a few minutes out of his relativistic travel to answer our questions. Make sure you visit his blog and read his answer to my question.

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GOING TO THE MOON AGAIN - The Dutch Are Going To The Moon With The Chinese

The Dutch Are Going To The Moon With The Chinese:

One of the defining characteristics of the New Space era is partnerships. Whether it is between the private and public sector, different space agencies, or different institutions across the world, collaboration has become the cornerstone to success. Consider the recent agreement between the Netherlands Space Office (NSO) and the Chinese National Space Agency (CNSA) that was announced earlier this week.



In an agreement made possible by the Memorandum of Understanding (MoU) signed in 2015 between the Netherlands and China, a Dutch-built radio antenna will travel to the Moon aboard the Chinese Chang’e 4 satellite, which is scheduled to launch in 2018. Once the lunar exploration mission reaches the Moon, it will deposit the radio antenna on the far side, where it will begin to provide scientists with fascinating new views of the Universe.



The radio antenna itself is also the result of collaboration, between scientists from Radboud University, the Netherlands Institute for Radio Astronomy (ASTRON) and the small satellite company Innovative Solutions in Space (ISIS). After years of research and development, these three organizations have produced an instrument which they hope will usher in a new era of radio astronomy.







Essentially, radio astronomy involves the study of celestial objects - ranging from stars and galaxies to pulsars, quasars, masers and the Cosmic Microwave Background (CMB) - at radio frequencies. Using radio antennas, radio telescopes, and radio interferometers, this method allows for the study of objects that might otherwise be invisible or hidden in other parts of the electromagnetic spectrum.



One drawback of radio astronomy is the potential for interference. Since only certain wavelengths can pass through the Earth's atmosphere, and local radio wave sources can throw off readings, radio antennas are usually located in remote areas of the world. A good example of this is the Very-Long Baseline Array (VLBA) located across the US, and the Square Kilometer Array (SKA) under construction in Australia and South Africa.



One other solution is to place radio antennas in space, where they will not be subject to interference or local radio sources. The antenna being produced by Radbound, ASTRON and ISIS is being delivered to the far side of the Moon for just this reason. As the latest space-based radio antenna to be deployed, it will be able to search the cosmos in ways Earth-based arrays cannot, looking for vital clues to the origins of the universe.



As Heino Falke - a professor of Astroparticle Physics and Radio Astronomy at Radboud - explained in a University press release, the deployment of this radio antenna on the far side of the Moon will be an historic achievement:

“Radio astronomers study the universe using radio waves, light coming from stars and planets, for example, which is not visible with the naked eye. We can receive almost all celestial radio wave frequencies here on Earth. We cannot detect radio waves below 30 MHz, however, as these are blocked by our atmosphere. It is these frequencies in particular that contain information about the early universe, which is why we want to measure them.”

As it stands, very little is known about this part of the electromagnetic spectrum. As a result, the Dutch radio antenna could be the first to provide information on the development of the earliest structures in the Universe. It is also the first instrument to be sent into space as part of a Chinese space mission.



Alongside Heino Falcke, Marc Klein Wolt - the director of the Radboud Radio Lab - is one of the scientific advisors for the project. For years, he and Falcke have been working towards the deployment of this radio antenna, and have high hopes for the project. As Professor Wolt said about the scientific package he is helping to create:

“The instrument we are developing will be a precursor to a future radio telescope in space. We will ultimately need such a facility to map the early universe and to provide information on the development of the earliest structures in it, like stars and galaxies.”

Together with engineers from ASTRON and ISIS, the Dutch team has accumulated a great deal of expertise from their years working on other radio astronomy projects, which includes experience working on the Low Frequency Array (LOFAR) and the development of the Square Kilometre Array, all of which is being put to work on this new project.







Other tasks that this antenna will perform include monitoring space for solar storms, which are known to have a significant impact on telecommunications here on Earth. With a radio antenna on the far side of the Moon, astronomers will be able to better predict such events and prepare for them in advance.



Another benefit will be the ability to measure strong radio pulses from gas giants like Jupiter and Saturn, which will help us to learn more about their rotational speed. Combined with the recent ESO efforts to map Jupiter at IR frequencies, and the data that is already arriving from the Juno mission, this data is likely to lead to some major breakthroughs in our understanding of this mysterious planet.



Last, but certainly not least, the Dutch team wants to create the first map of the early Universe using low-frequency radio data. This map is expected to take shape after two years, once the Moon has completed a few full rotations around the Earth and computer analysis can be completed.



It is also expected that such a map will provide scientists with additional evidence that confirms the Standard Model of Big Bang cosmology (aka. the Lambda CDM model). As with other projects currently in the works, the results are likely to be exciting and groundbreaking!



Further Reading: Radbound University

The post The Dutch Are Going To The Moon With The Chinese appeared first on Universe Today.

DISCOVER THE COSMOS - Sunrise Solstice over Stonehenge

Sunrise Solstice over Stonehenge:

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2016 June 20

Sunrise Solstice over Stonehenge

Image Credit & Copyright: Max Alexander, STFC, SPL


Explanation: Today the Sun reaches its northernmost point in planet Earth's sky. Called a solstice, the date traditionally marks a change of seasons -- from spring to summer in Earth's Northern Hemisphere and from fall to winter in Earth's Southern Hemisphere. The featured image was taken during the week of the 2008 summer solstice at Stonehenge in United Kingdom, and captures a picturesque sunrise involving fog, trees, clouds, stones placed about 4,500 years ago, and a 4.5 billion year old large glowing orb. Even given the precession of the Earth's rotational axis over the millennia, the Sun continues to rise over Stonehenge in an astronomically significant way.

Tomorrow's picture: prickly pinwheel

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SPIRAL GALAXY - NGC 6814: Grand Design Spiral Galaxy from Hubble

NGC 6814: Grand Design Spiral Galaxy from Hubble:

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2016 June 21

Explanation: In the center of this serene stellar swirl is likely a harrowing black-hole beast. The surrounding swirl sweeps around billions of stars which are highlighted by the brightest and bluest. The breadth and beauty of the display give the swirl the designation of a grand design spiral galaxy. The central beast shows evidence that it is a supermassive black hole about 10 million times the mass of our Sun. This ferocious creature devours stars and gas and is surrounded by a spinning moat of hot plasma that emits blasts of X-rays. The central violent activity gives it the designation of a Seyfert galaxy. Together, this beauty and beast are cataloged as NGC 6814 and have been appearing together toward the constellation of the Eagle (Aquila) for roughly the past billion years.

CIRRUS CLOUDS OVER PARIS - DISCOVER THE COSMOS

Cirrus over Paris:

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2016 June 22

Cirrus over Paris

Image Credit & Copyright: Bertrand Kulik


Explanation: What's that over Paris? Cirrus. Typically, cirrus clouds appear white or gray when reflecting sunlight, can appear dark at sunset (or sunrise) against a better lit sky. Cirrus are among the highest types of clouds and are usually thin enough to see stars through. Cirrus clouds may form from moisture released above storm clouds and so may herald the arrival of a significant change in weather. Conversely, cirrus clouds have also been seen on Mars, Jupiter, Saturn, Titan, Uranus, and Neptune. The featured image was taken two days ago from a window in District 15, Paris, France, Earth. The brightly lit object on the lower right is, of course, the Eiffel Tower.

Tomorrow's picture: open space

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FULL MOON - Solstice Dawn and Full Moonset

Solstice Dawn and Full Moonset:

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2016 June 23

Explanation: A Full Moon sets as the Solstice Sun rises in this June 20 dawn skyscape. Captured from a nearby peak in central California, planet Earth, the scene looks across the summit of Mount Hamilton and Lick Observatory domes on a calendar date that marks an astronomical change of seasons and hemispherical extremes of daylight hours. Earth's shadow stretches toward the Santa Cruz Mountains on the western horizon. Just above the atmospheric grey shadowband is a more colorful anti-twilight arch, a band of reddened, backscattered sunlight also known as the Belt of Venus. The interplay of solstice dates and lunar months does make this solstice and Full Moon a rare match-up. The next June solstice and Full Moon will fall on the same calendar date on June 21, 2062.

CONSTELLATION SAGITTARIUS - Sagittarius Sunflowers

Sagittarius Sunflowers:

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2016 June 24

Sagittarius Sunflowers

Image Credit & Copyright: Andrew Campbell


Explanation: These three bright nebulae are often featured in telescopic tours of the constellation Sagittarius and the crowded starfields of the central Milky Way. In fact, 18th century cosmic tourist Charles Messier cataloged two of them; M8, the large nebula left of center, and colorful M20 near the bottom of the frame The third, NGC 6559, is right of M8, separated from the larger nebula by dark dust lanes. All three are stellar nurseries about five thousand light-years or so distant. The expansive M8, over a hundred light-years across, is also known as the Lagoon Nebula. M20's popular moniker is the Trifid. In the composite image, narrowband data records ionized hydrogen, oxygen, and sulfur atoms radiating at visible wavelengths. The mapping of colors and range of brightness used to compose this cosmic still life were inspired by Van Gogh's famous Sunflowers. Just right of the Trifid one of Messier's open star clusters, M21, is also included on the telescopic canvas.

Tomorrow's picture: strawberry to honey

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DISCOVER THE COSMOS - From Alpha to Omega in Crete

From Alpha to Omega in Crete:

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2016 June 29

Explanation: This beautiful telephoto composition spans light-years in a natural night skyscape from the island of Crete. Looking south, exposures both track the stars and record a fixed foreground in three merged panels that cover a 10x12 degree wide field of view. The May 15 waxing gibbous moonlight illuminates the church and mountainous terrain. A mere 18 thousand light-years away, huge globular star cluster Omega Centauri (NGC 5139) shining above gives a good visual impression of its appearance in binoculars on that starry night. Active galaxy Centaurus A (NGC 5128) is near the top of the frame, some 11 million light-years distant. Also found toward the expansive southern constellation Centaurus and about the size of our own Milky Way is edge on spiral galaxy NGC 4945. About 13 million light-years distant it's only a little farther along, and just above the horizon at the right.

SKY BRIGHTNESS - The New World Atlas of Artificial Sky Brightness

The New World Atlas of Artificial Sky Brightness:

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2016 June 30

Explanation: How far are you from a naturally dark night sky? In increasing steps, this world map (medium | large) shows the effect of artificial night sky brightness on the visual appearance of the night sky. The brightness was modeled using high resolution satellite data and fit to thousands of night sky brightness measurements in recent work. Color-coded levels are compared to the natural sky brightness level for your location. For example, artificial sky brightness levels in yellow alter the natural appearance of the night sky. In red they hide the Milky Way in an artificial luminous fog. The results indicate that the historically common appearance of our galaxy at night is now lost for more than one-third of humanity. That includes 60% of Europeans and almost 80% of North Americans, along with inhabitants of other densely populated, light-polluted regions of planet Earth.

JUPITER PLANET - Juno Approaching Jupiter

Juno Approaching Jupiter:

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2016 July 1

Explanation: Approaching over the north pole after nearly a five-year journey, Juno enjoys a perspective on Jupiter not often seen, even by spacecraft from Earth that usually swing by closer to Jupiter's equator. Looking down toward the ruling gas giant from a distance of 10.9 million kilometers, the spacecraft's JunoCam captured this image with Jupiter's nightside and orbiting entourage of four large Galilean moons on June 21. JunoCam is intended to provide close-up views of the gas giant's cloudy zoned and belted atmosphere. On July 4 (July 5 UT) Juno is set to burn its main engine to slow down and be captured into its own orbit around the giant planet. If all goes well, it will be the first spacecraft to orbit the poles of Jupiter, skimming to within 5,000 kilometers of the Jovian cloud tops during the 20 month mission.

UFOS IN RUSSIA - Top Secret Alien and UFO Base in Russia

UFO, HOW IT WORKS ? Lets go inside of alien spaceship!

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UFO MADE AT HOME - UFO ANTI GRAVITY FROM HOUSEHOLD ITEMS

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ASTRONOMICAL SUMMER - Seeking the Summer Solstice

Seeking the Summer Solstice:

Can you feel the heat? If you find yourself north of the equator, astronomical summer kicks off today with the arrival of the summer solstice. In the southern hemisphere, the reverse is true, as today's solstice marks the start of winter.



Thank our wacky seasons, and the 23.4 degree tilt of the Earth's axis for the variation in insolation. Today, all along the Tropic of Cancer at latitude 23.4 degrees north, folks will experience what's known as Lahiana Noon, as the Sun passes through the zenith directly overhead. Eratosthenes first noted this phenomena in 3^rd century BC from an account in the town of Syene (modern day Aswan), 925 kilometers to the south of Alexandria, Egypt. The account mentioned how, at noon on the day of the solstice, the Sun shined straight down a local well, and cast no shadows. He went on to correctly deduce that the differing shadow angles between the two locales is due to the curvature of the Earth, and went on to calculate the curvature of the planet for good measure. Not a bad bit of reasoning, for an experiment that you can do today.







And although we call it the Tropic of Cancer, and the astrological sign of the Crab begins today as the Sun passes 90 degrees longitude along the ecliptic plane as seen from Earth, the Sun now actually sits in the astronomical constellation of Taurus on the June northward solstice. Thank precession; live out a normal 72 year human life span, and the solstice will move one degree along the ecliptic—stick around about 26,000 years, and it will complete one circuit of the zodiac. That's something that your astrologer won't tell you.







The solstice in the early 21^st century actually falls on June 20th, thanks to the 'reset' the Gregorian calendar received in 2000 from the addition of a century year leap day. The actual moment the Sun reaches its northernmost declination today and slowly reverses its apparent motion is 22:34 Universal Time (UT).  In 2016, the Moon reaches Full just 11 hours to the solstice. The last time a Full Moon fell within 24 hours of a solstice was December 2010, and we had a total lunar eclipse to boot. Such a coincidence won't occur again until December 2018. You get a good study in celestial mechanics 101 tonight, as the Full Moon rises opposite to the setting Sun. The Moon occupies the southern region of the sky where the Sun will reside this December during the other solstice, when the Full Moon will then ride high in the night sky, and gets ever higher as we head towards a Major Lunar Standstill in 2025.







Of course, this motion of the Sun through the year is all an illusion from our terrestrial biased viewpoint. We're actually racing around the Sun to the tune of 30 kilometers per second. You wouldn't know it at summer heats up in the northern hemisphere, but we're headed towards aphelion or the farthest point from the Sun for the Earth on July 4th at 152 million kilometers or 1.017 astronomical units (AU) distant. And the latest sunset as seen from latitude 40 degrees actually occurs on June 27^th at 7:33 PM (not accounting for Daylight Saving Time) go much further north (like the Canadian Maritimes or the UK) and true astronomical darkness never occurs in late June.



And speaking of the Sun, we're wrapping up the end of the 11 year solar cycle this year... and there are hints that we may be in for another profound solar minimum similar to 2009. We've already had a brief spotless stretch last month, and some solar astronomers have predicted that solar cycle #25 may be absent all together. This means a subsidence in aurorae, and an uncharacteristically blank Sol.



But don't despair and pack it in for the summer. As a consolation prize, high northern latitudes have in recent years played host to electric blue noctilucent clouds near the June solstice. Also, the International Space Station enters a second period of full illumination through the entire length of its orbit from July 26th to 28th, making for the possibility of seeing multiple passes in a single night.







And folks in the Islamic world (and travelers such as ourselves currently in Morocco) can rejoice, as the Full Moon means that we're half way through the fasting lunar month Ramadan. This is an especially tough one, as Ramadan 2016 goes right through the summer solstice, making for only a brief six hour span to break the fast each  night and prepare for another 18 hour long stretch... and to repeat this pattern for 29 days straight. It's a fascinating time of night markets and celebration, but for travelers, it also means odd opening hours and delays.







See any curious solstice shadow alignments in your neighborhood today?



Happy Lahiana Noon... from here on out, northern viewers slowly start to take back the night!





The post Seeking the Summer Solstice appeared first on Universe Today.

GALAXY AND PLANETS - Beyond Bristlecone Pines

Galaxy and Planets Beyond Bristlecone Pines:

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2016 June 19

Explanation: What's older than these ancient trees? Nobody you know -- but almost everything in the background of this picture. The trees are impressively old -- each part of the Ancient Bristlecone Pine Forest located in eastern California, USA. There, many of the oldest trees known are located, some dating as far back as about 5,000 years. Seemingly attached to tree branches, but actually much farther in the distance, are the bright orbs of Saturn (left) and Mars. These planets formed along with the Earth and the early Solar System much earlier -- about 4.5 billion years ago. Swooping down diagonally from the upper left is the oldest structure pictured: the central band of our Milky Way Galaxy -- dating back around 9 billion years. The featured image was built from several exposures all taken from the same location -- but only a few weeks ago.

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CROP CIRCLES MYSTERY - Secret Messages in 2016's first 6 crop circles

CROP CIRCLES FROM ALIENS - - Crop formations - Messages for Humanity. Lecture by Alan Foster

MYSTERY - Unexplained Dimmings in KIC 8462852

Unexplained Dimmings in KIC 8462852:

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2016 June 13

Explanation: Why does star KIC 8462852 keep wavering? Nobody knows. A star somewhat similar to our Sun, KIC 8462852 was one of many distant stars being monitored by NASA's robotic Kepler satellite to see if it had planets. Citizen scientists voluntarily co-inspecting the data along with computers found this unusual case where a star's brightness dropped at unexpected times by as much as 20 percent for as long as months -- but then recovered. Common reasons for dimming -- such as eclipses by orbiting planets or stellar companions -- don't match the non-repetitive nature of the dimmings. A currently debated theory is dimming by a cloud of comets or the remnants of a shattered planet, but these would not explain data indicating that the star itself has become slightly dimmer over the past 125 years. Nevertheless, featured here is an artist's illustration of a planet breaking up, drawn to depict NGC 2547-ID8, a different system that shows infrared evidence of such a collision. Recent observations of KIC 8462852 did not detect the infrared glow of a closely orbiting dust disk, but gave a hint that the system might have such a disk farther out. Future observations are encouraged and creative origin speculations are sure to continue.

GW151226: A Second Confirmed Source of Gravitational Radiation

GW151226: A Second Confirmed Source of Gravitational Radiation:

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2016 June 15


GW151226: A Second Confirmed Source of Gravitational Radiation

Illustration Credit: LIGO, NSF


Explanation: A new sky is becoming visible. When you look up, you see the sky as it appears in light -- electromagnetic radiation. But just over the past year, humanity has begun to see our once-familiar sky as it appears in a different type of radiation -- gravitational radiation. Today, the LIGO collaboration is reporting the detection of GW151226, the second confirmed flash of gravitational radiation after GW150914, the historic first detection registered three months earlier. As its name implies, GW151226 was recorded in late December of 2015. It was detected simultaneously by both LIGO facilities in Washington and Louisiana, USA. In the featured video, an animated plot demonstrates how the frequency of GW151226 changed with time during measurement by the Hanford, Washington detector. This GW-emitting system is best fit by two merging black holes with initial masses of about 14 and 8 solar masses at a redshift of roughly 0.09, meaning, if correct, that it took roughly 1.4 billion years for this radiation to reach us. Note that the brightness and frequency -- here mapped into sound -- of the gravitational radiation peaks during the last second of the black hole merger. As LIGO continues to operate, as its sensitivity continues to increase, and as other gravitational radiation detectors come online in the next few years, humanity's new view of the sky will surely change humanity's understanding of the universe.

Tomorrow's picture: open space

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