Tuesday, May 31, 2011

Party stars and raining glitter, 05.31.11

Astronomers have recently analyzed some rather sparkly data from the Spitzer telescope. It seems HOPS-68, a star in the constellation Orion, is raining glitter. Yes, glitter.
Image credit: NASA/Tom Trower.
The star, it has been found, is actually raining small crystals of olivine, a mineral commonly found in periodots and green sand, particularly from Hawai’i, like these olivine samples pictured here.
The findings are puzzling, though. According to Tom Megeath of the University of Toledo in Ohio, a lead researcher in the case, “you need temperatures as hot as lava to make these crystals.” The problem, though, is that the cloud surrounding the proto-star is approximately 280 degrees Fahrenheit below zero, so it is impossible they could have formed in the star’s atmosphere in its current state. The prevailing theory is that the crystals formed when the star was hot and wild, and were swept out in solar winds and jets through the years. It seems they are still close enough to be affected by the star’s gravity, however. As time wore on and things began to settle down, the crystals began falling back down on the star, creating the glitter rain effect observed by astronomers.
The same theories surround the green haze created by olivine particles in the vicinity of comets because, well, they just might actually be great clumps of the stuff frozen together. According to Charles Poteet, the lead author on the project, it is probable that many of these crystals formed early on and were carried to the outer rim of the solar system as time wore on. Then, they eventually clumped together as they began to freeze, and consequently became the orbiting objects they are now, comets. That is how the theory goes, any way.
In any case, this star may be cold, but it sure knows how to party! Who needs a disco ball when you can have crystal rain?
Credit: NASA/JPL.

Monday, May 23, 2011

Loner planets, 05.23.11

Researchers recently gathered evidence for the existence of at least 10 free-floating planets that are roughly the same mass as Jupiter.
The Microlensing Observations in Astrophysics (MOA), a joint project between Japan and New Zealand, and the Optical Gravitational Lensing Experiment (OGLE) survey group, made the discovery using telescopes that scan the center of the Milky Way galaxy. By measuring light as one star or planet passes in front of a distant star, the scientists can narrow down the possibilities of what the object may be. From the data they have gathered, they have discovered at least 10 free-floating planets (planets that do not orbit any particular star). Not only that, but based on census-style calculations, they say that for every star in our galaxy, there could be at least two such wandering worlds.
Image credit: NASA/JPL-Caltech.
So where did they come from? Several theories have been formed, and both seem equally plausible. One theory is that the planets were thrown out of their solar systems in the early centuries after their creation, due to the turbulence of all the new gravitational fields. Since they are not orbiting any one particular star, they have dropped into their own stable orbits around the center of the Milky Way.
The other theory regards how the planets formed. Brown dwarfs, a classification of stars, are extremely cool for stars (about the same temperature as a fresh cup of coffee), and are about as small as planets. Could these loner planets have formed the same way as those stars, or did they form the same way as the other planets and just get separated from the rest of their solar system? The researchers say both theories are just as likely.
 Credit: NSF.

Wednesday, May 18, 2011

Space junkies fed up with all the junk, 05.18.11

According to General William Shelton, commander of the U.S. Air Force Space Command, there are well over 20,000 man-made junk objects floating around earth, collectively referred to as “detritus.” Those pieces of trash are just the ones that have been logged and are being tracked. According to Gen. Shelton, it is possible that at least 10 times that much is out there now; we just cannot detect it.
This computer illustration depicts the density of space junk around Earth in low-Earth orbit.
Image credit: ESA.

So where did all of this space junk come from? It is not just dust and rocks floating around, but actual pieces of satellites, missiles, and space ships floating around planet earth. 50 years in the space program is a lot of time for garbage to build up. Some of the pieces are satellites that served their purpose and either “died” or were deactivated, some are extra parts that fell off or were blown off of spacecraft, and still other pieces came from satellites that collided with other objects or were blown up intentionally by missiles, as in a fairly recent test by China (their anti-satellite or ASAT test) in 2007. The pieces of detritus can vary in size from just a few millimeters to a few meters across, and can be travelling at dangerously high speeds in a geosynchronous orbit around earth. This creates serious headaches for operators of live satellites, space shuttles, and the International Space Station, because all active instruments in space must alter their orbit and stay at least one mile away from every single piece of debris orbiting our planet. This computer generated graphic is meant to illustrate the approximate density of the garbage at this point.
A problem created by the 50 or so individual nations now involved in space exploration, it is impossible to point the finger at any one group for causing the mess. Therein lies the problem in getting cooperation for cleanup. If something is not done soon to either alter practices or make a serious effort to reduce the trash, experts project the amount of detritus to triple by 2030.
 Credit: SPACE.com.

Friday, May 6, 2011

Meteor shower

Just a reminder:

Keep your eyes peeled tonight for a meteor shower! It is one of the milder showers, but if you are far away from light pollution, your might be able to catch a glimpse of a few. 

This particular shower is caused by debris left over from Halley's comet, discovered by Edmond Halley in the early 1700s.

"Spinstars" may have helped seed the universe, 05.02.11

NGC 6522. Image credit: Anglo-Australian Observatory and David Malin. 
Astrophysicists have theorized a new type of star that they claim may have helped seed our galaxy with heavier elements. Called "spinstars," they are thought to have been super-massive stars that spun in excess of one million miles per hour.

Using data recently gathered from the Very Large Telescope (VLT) at the European Southern Observatory in the mountains of Chile, astrophysicist Cristina Chiappini and her colleagues have gathered data from NGC 6522, a globular cluster, and theorized that the spinstars would explain the rapid and widespread dispersal of heavier elements in the universe. The layers of stars hardly ever mix together, but the extreme rotation speeds of a spinstar would cause the layers to overlap and blend a little, like a stellar emulsion, and spark nuclear reactions that would eventually cause the formation of heavy elements strontium and yttrium, rare elements that have been found at perplexingly high levels in older stars Chiappini studied.

For comparison, SPACE.com reminds us that our own star, the sun, rotates at only about 4,400 miles per hour--fast by any stretch of the imagination, but a snail's pace compared to the proposed spinstars.

It is a pity no spinstars have been found to date, either. They would probably look quite strange. The centrifugal force from rotating so quickly actually causes objects in space to flatten out in the center. Even our own sun is a little chubby in the middle because of its rotation speed.
Altair. Image credit: SPACE.com.

Take this star, Altair, for example, a star that spins a good deal faster than our sun. As fast as Altair spins, an actual spinstar would probably look even more obscured, like a football, or maybe even just a rounded disc with a lump in the center.

Chiappini says she and her team have already reserved more research time to use the VLT, gather more data and, hopefully, evidence to help test their theories.

Credit: SPACE.com.