The Galaxy from the perspective of the Space Jockey

It would seem the Space Jockey must of mapped out almost every star in the sector it seems. But does it map out the hidden galaxies that are hiding in plain sight?

This part of space may look like nothing special, but it's actually a packed "galaxy city" composed of thirty ancient galaxies.This find took thousands of hours of observation before anyone noticed.

Located 10.5 billion light-years away, this galaxy cluster is the most distant and, consequently, the oldest known example of a red galaxy cluster. Red color gives us vital clues about the mass and configuration of the galaxies. We are catching this cluster way back in time in its earliest development. This discovery was found at  the Carnegie Observatories where its astronomers say it could evolve to a giant, dense cluster of over a thousand galaxies.

This area of space has been under constant observation by a number of telescopes, including Hubble, and yet nobody suggested there was a galaxy cluster there. That's because this cluster is extremely faint and essentially invisible in all but a very narrow slice of the infrared spectrum.

The astronomers were able to detect the cluster using the new FourStar camera on the Magellan Bade Telescope, which is used to provide extremely accurate measurements of the distances between Earth and thousands of different galaxies. They in turn build up a 3D map of this area of the universe. Astronomers used this data to spot a strangely high concentration of galaxies at this particular point in space and time, revealing the existence of this cluster.

Solar Wind destroying your Atmosphere

Well not ours per say because here on earth we happen to have a magnetic field protecting us. However over at Venus things get very messy when a solar storm hits its atmosphere.

The earth's magnetic field shields us from most of the effects of the solar wind. But Venus has no such field, meaning its atmosphere is the only defense against the solar wind.

Solar wind from the sun comes at about a million miles an hour, and hits close to Earth at about 50,000 miles before it hits the magnetosphere. Most of the wind flows around this magnetic shield, meaning we're protected from most, though certainly not all of what the solar wind carries. But on Venus, the solar wind routinely reaches its atmosphere, which is where NASA  observed some seriously bizarre space weather effects.

When the solar wind hits something. That something being the planet's magnetic field can sometimes create a phenomenon known as a hot flow anomaly. In these, the solar wind temporarily reverses direction, with material shooting backwards. This sudden rush of material creates an explosion. We've seen such anomalies around Earth's magnetic fields, as well as around Saturn and possibly Mars as well.

The question NASA's researchers set out to find was if these anomalies would also occur if the planet, in this case Venus, has no magnetic field.

Right now the ESA's Venus Express mission that is currently in orbit around the planet have mapped out the effect of this anomalies.

Although this satellite can't actually measure space weather, some of its instruments would have a telltale magnetic response to a hot flow anomaly that happened in its vicinity. After 3 years of data, they discovered such an explosion occurred on Venus. Exactly what these hot flow anomalies look like on Venus is an open question.

In the source below there is a video (which you should check out) showing the flow anomalies most likely occur right near the surface of the planet. Without a magnetic field to keep the explosions far away from the planet, Venus likely experiences the full brunt of these plasma shockwaves. The only good news for Venus is that without a magnetic field to excite the plasma in the solar wind, the explosions are likely a bit more mild than those that occur near Earth. However, that hardly makes up for the fact that the entire Venusian atmosphere can explode at any moment.

http://www.nasa.gov/mission_pages/sunearth/news/venus-explosions.html

Rewriting the textbook, maybe

Somewhere in the sky theres a dwarf galaxy located just 59 million light years away, making it one of the closest galaxies near us. But because most of its stars are still just starting out, it's like a portal to the early universe.

The galaxy, whose full name I Zwicky 18, appears to be much younger than most of its galactic neighbors, including our own Milky Way. While the Hubble Telescope has picked up the faint traces of some ten billion year old stars in the galaxy, almost all the stars we can see are just a billion years old.

While it might not be a perfect mirror of young galaxies from the early universe, it's definitely the best example we can get at this close range. Young Galaxies are very poor in heavy elements, just like we would expect early galaxies to be. That all makes I Zw 18 an interesting subject of research, and the latest findings from the Center for Astrophysics of the University of Porto (CAUP) could have big implications for how we look at ancient, faraway galaxies.

Astronomers from the CAUP discovered a huge gas halo all around I Zw 18. This halo is about 16 times larger than the part of the star-filled portion of the galaxy, and in fact it is completely devoid of any stars at all. It's apparently created by the intense star formation going on in the rest of the galaxy. The energy released by the star formation makes the halo exactly the same brightness as the star-filled part of the galaxy.

That may seem something minor, but if this phenomenon holds true of other young galaxies, then astronomers might not be able to tell whether the light they see is coming from stars or gas. Until now, astronomers assumed that the luminosity of a galaxy was a good proxy for estimating the number of stars in a galaxy that's too far away.

But if up to 50% of the apparent starlight is actually coming from surrounding gas, then that would mean there are far fewer stars in these galaxies than we thought, which might mean we have to reclassify these apparently fully formed galaxies as one that are actually still only developing. This could help us see the early galaxy in a whole new light. Assuming of course, that we can actually figure out a way to tell the two different types of light apart.


http://www.aanda.org/index.php?option=com_article&access=doi&doi=10.1051/0004-6361/201117551&Itemid=129

The Lonely Blackhole

Unique mid-sized black hole is the lonely survivor of a shredded galaxy.

This is the Hubble Telescope's latest and clearest yet image of the galaxy ESO 243-49. Astronomers have been watching this galaxy for a while now, because it's likely the only known medium-sized black hole in the sky right now.

The black hole at the center of this galaxy is known as HLX-1. Located 290 million light-years away, this black hole appears to fit somewhere right between the small black stars that form when a giant star collapses and the supermassive black holes that are found at the centers of galaxies. No one have an idea on how these supermassive black holes come to exist. The best explanation is that they are formed by the repeated collisions of galaxies, which smashes black holes together to form larger and larger mergers. For that to work, we should be seeing black holes that are still in the middle of the transition from small to supermassive.

Astronomers are eager to learn more about its particular origins. Now, thanks to Hubble, it is known that it is surrounded by a bunch of young massive blue stars that form a cluster some 250 light-years across. Hubble scientist Sean Farrell explains:

"Before this latest discovery, we suspected that intermediate-mass black holes could exist, but now we understand where they may have come from. The fact that there seems to be a very young cluster of stars indicates that the intermediate-mass black hole may have originated as the central black hole in a very-low-mass dwarf galaxy. The dwarf galaxy might then have been swallowed by the more massive galaxy, just as happens in our Milky Way."

The cluster is a crucial clue because there's no way it could have formed under normal circumstances so far from the center of the galaxy. This suggests that they were likely formed when HLX-1 was captured by its current galaxy in a collision with its original home, most likely a dwarf galaxy. The black hole was the central black hole in this tiny galaxy, but its stars were ripped away in the collision, which also would have compressed the surround gas and kicked off the star formation that created these blue giants.

This particular collision was fairly recent, the stars are only about 200 million years old and HLX-1 is still just beginning the process of feeding and growing.

Hidden Pluto

Pluto is about forty times the distance from the Sun as Earth. But our Solar System is over 50000 times across that which means it could be hiding some huge blackbody.

In recent years, astronomers have discovered a bunch of planets located at least 100 astronomical units away from their host stars. These planets are gas giants. The problem is that they dont emit light well unless they are close to something bright like the sun. This is something very different the dwarf planets like Pluto and Eris discovered in our solar system's Kuiper Belt and beyond.

There's almost no chance that these giant planets could have formed as part of their host star's planetary disc, considering their immense distance away. That strongly suggests that these are former rogue planets captured by the star's gravity. Scientists at Harvard-Smithsonian Center and Peking University's Kavli Institute tries to figure out just how often we can expect stars; potentially including those like our own Sun; to capture these giant wandering planets.

Quoted by ScienceNOW report:

"Because most stars are born with others, Perets and Kouwenhoven ran computer simulations to see what happens when a star cluster contains free-floating planets. If the number of free-floating planets equals the number of stars, then 3% to 6% of the stars succeed in capturing a planet, and some stars capture two or three. Most of the captured planets end up hundreds or thousands of times farther from their stars than Earth is from the sun. Furthermore, most captured planets have orbits tilted to those of native-born planets, and half the captured planets revolve around their stars backward."

Their work depends on having a good grasp of how many rogue planets there really are, and we can't be sure our current estimates, which suggest there area as many wandering planets as there are stars, is accurate. But if these results are accurate, then our Sun, whose mass is slightly above average, had a real chance of capturing one or more planets eons ago.

The chances aren't huge but probably only a few percent higher. If their numbers are accurate, then the possibility of such a planet definitely exists.

What do you see in this picture?

This is not a rorschach test for psychology but an image of NGC 3324 or whatever you are imagining of this silhollet .

The fierce ultraviolet radiation given off by the young stars, NGC 3324, has carved this giant cavity in space. Because of the boundary between different gases it looks an awful lot like a person's profile.

The astronomers at the La Silla Observatory in Chile's Coquimbo Region have dubbed this the Gabriela Mistral Nebula. So how was this boundary created between the different parts of the nebula?

A deposit of gas and dust in the NGC 3324 region fueled a burst several millions of years ago and led to the creation of several hot stars that are apparent in the picture. Stellar winds and intense radiation from these stars have blown open a hollow in the surrounding gas and dust. The ultraviolet radiation from the hot stars knocks electrons out of hydrogen atoms thus ionizing it, which are then recaptured, leading to a crimson colored glow as the electrons jumps through the energy levels, showing the extent of the local diffuse gas. Other colors come from other elements, with the characteristic glow from ionized oxygen making the central parts appear greenish-yellow.

Shrinking of the North Star

The North Star, or Polaris as astronomers calls it, has been guiding sailors and many others at night for centuries. Now astronomers found out that all is not well with its light cycles, it turns out that Polaris is losing mass equivalent to the earth each year. The idea was proposed by Hilding Neilson and his team at the University of Bonn. The researchers weighed Polaris which is a supergiant main star in the Polaris multiple star system by monitoring how its light cycles dims and brightens.

By detecting a star's light cycle one can know the mass of the star. How this works is like most supergiant stars like our sun is made up of gases in the layers around the core where fusion occurs. The gravitational force of the star pulls the outermost gas inward creating an opaque layer just below the surface. This surface acts like a pressure tank which hold light in. Once it reaches its limit it releases the light build up at once like a shaken bottle of coke. The light buildup will heat up the opaque layer expanding it and becomes transparent. After energy is disperse from the heated opaque layer it will be pulled down again the cycle continues.

The thing is that Polaris's light cycle hasn't remained constant. Observations made in 1844 reveal Polaris's pulse used to be 12 minutes slower than it is now, and 168 years of data suggest that Polaris's pulse regularly decreases by about 4.5 seconds each year. The best explanation from Neilson, is that Polaris is dispersing an earth's worth of mass into space every year, which would throw off the inner workings of the light cycle just enough to account for this big drop.

The good news is that Neilson says this mass loss is likely to be temporary in the star's life. The star isn't going to disappear anytime soon with this method of dispersing mass. Still this wont matter because Polaris isnt going to be our north star anymore. In another 1000 years Gamma Cephei will replace the alignment where Polaris is. So in the future we can still be certain that we can still navigate the sea by stars.


http://m.iopscience.iop.org/2041-8205/745/2/L32