Space Fan News #58: Double Your Astronomy Pleasure (Almost)
Uploaded by tdarnell on 16.03.2012
Transcript:
Hello Space Fans and welcome to another edition of Space Fan News.
Now I know I talk a lot about gravitational lensing here on Space Fan News, but usually
it's a galaxy or cluster of galaxies doing the lensing.
And when I talk about microlensing, there's usually a black hole or a star acting as the
lens.
But this week, Hubble has observed quasars that are amplifying and distorting images
of galaxies that lie behind them.
Here's an example. What you see here are three different galaxies taken from the Sloan Digital
Sky Survey and embedded deep within each one is a quasar at the core. In each one you can
see the light from an even further and distant galaxy that lies way behind the foreground
galaxy containing the quasar, which is distorted into these funky little arcs.
This is the gravity of a quasar bending that distant light and forming it into a partial
ring.
As you know, gravitational lensing is pretty common, we see it everywhere, especially in
galaxy clusters where one galaxy is almost guaranteed to be in the way of another within
our line of sight. But this is the first time lensing has been seen from a quasi-stellar
object.
These quasars are supermassive black holes lying at the centers of these galaxies, they
are hundreds of millions to billions of times larger than stellar sized black holes, so
it makes perfect sense that they could be lenses. It takes highly massive objects to
make the kind of gravity necessary to bend light like this.
Now one really handy use of these quasar lenses is that it allows us to actually get the mass
of the host galaxy. You see, it's hard to measure the mass of a galaxy that a quasar
resides in because they are so bright, they block out all the other radiation from the
stars within that galaxy. Since we can't accurately measure the light, we don't get a good idea
of how many stars are there which means we can't get a good estimate of the mass.
BUT, by measuring these arcs and the amount of distortion created by the lens, we can
get an idea of the mass of the galaxy that created that lens in the first place.
The next step is to build a catalog of these "quasar-lenses" that will allow astronomers
to determine masses for a statistically significant number of quasar host galaxies and then compare
them with galaxies without quasars. This will allow give even more accurate estimates over
time.
Next, NASA releases a new catalog of the entire infrared sky from the Wide-field Infrared
Survey Explorer or (WISE) mission.
WISE was launched on Dec. 14, 2009, for the purpose of mapping the entire sky in the infrared.
It did that in 2010 with much better sensitivity than its predecessors.
It collected more than 2.7 million images taken at four infrared wavelengths, and it
captured everything from nearby asteroids to distant galaxies. Since then, the team
has been processing more than 15 trillion bytes of returned data.
The individual WISE exposures have been combined into an atlas of more than 18,000 images covering
the entire sky - and they looked through each one and found more than 560 million individual
objects. They put those into a catalog listing the infrared properties of each one. Most
of the objects are stars and galaxies, with about equal numbers of each.
And many of them have never been seen before.
WISE also saw a lot of near-Earth asteroids, and it found that there are significantly
fewer mid-size objects than previously thought. It also confirmed that NASA has found more
than 90 percent of the largest near-Earth asteroids.
Oh you infrared portion of the spectrum, where would we be without you?
Next, it turns out the Hubble Space Telescope is better at resolving things that Charles
Messier.
For those who don't know, Charles Messier made a catalog of 110 objects in 1764. He
had a bunch of telescopes, but his favorite was a 7.4 inch reflector that he used to create
his catalog with. He scanned the skies and made note of all the fuzzy patches he saw.
Some of these were galaxies, but he didn't know about those in the 18th century, so he
called them all nebulae.
Over the years, as telescopes got larger, these fuzzy patches became better and better
resolved, culminating in an amazing image of M9, the 9th object recorded by Messier.
Here's roughly what Charles Messier saw.
And here's how that looks under the eyepiece of the Hubble Space Telescope.
This is the most detailed image ever taken of M9. It is a globular cluster, a spherical
swarm of very old stars near the center of our galaxy and lies about 25,000 light years
from us.
Globular clusters harbor some of the oldest stars in our galaxy, born when the Universe
was just a few billion years old. The stars of M9 have a markedly different composition
than stars like our Sun, and they are enriched with far fewer heavier elements.
For example, the elements crucial to life on Earth, like oxygen and carbon, and the
iron that makes up our planet’s core, are very scarce in Messier 9 and clusters like
it. This is because the Universe’s heavier elements were gradually formed in the cores
of stars, and in supernova explosions. When the stars of Messier 9 formed, there were
far smaller quantities of these elements in existence.
Next, what can you do with a giant pair of binoculars named after a sandwich?
Lots of things, but one thing you can do really well apparently is cancel out the blurring
effects of the Earth's atmosphere.
This week, astronomers from the Large Binocular Telescope, or BLT (oh... that's LBT…. never
mind), released the first series of scientific results showing its best-in-the-world performance
in canceling out that blur.
Those were the words they used: "Best in the world".
Located on Mt. Graham in southeastern Arizona, the LBT sports two giant 8.4 meter mirrors
(that's 27.5 feet). It has two of those…
But the cool part is in the secondary mirrors. These mirrors vibrate and bend really fast
to cancel out the distorted wavefronts caused by starlight traveling through a turbulent
atmosphere. As the starlight hits the upper part of our atmosphere, the distorted wavefront
of that incoming light is measured and then - in the time it takes the light to go from
the top of our atmosphere to the ground - a canceling waveform is calculated which bends
the secondary and removes the distortion before the light hits the telescope.
It's called adaptive optics and to ground-based telescopes it is just like downtown because
it lets them get the same results that only a telescope in space can get.
And apparently, no one is better at doing that than the BLT - that's LBT. Oh great,
now I'm hungry.
Finally, using the original neutrino beam used back in September by the OPERA experiment,
the ICARUS team have announced that their findings of the arrival times of neutrinos
blasted from CERN are within the speed limits set by relativity.
The ICARUS experiment was another effort that used the same beam that OPERA used, but it
had a different and independent timing source. Well, they released this week that their results
don't contradict Einstein, they were all well within the speed limit.
Remember, I last reported to you that the GPS timing signals used by OPERA that were
piped underground were found to have faulty connections, making the timing used in OPERA
more than a little suspect, so they need to do it again.
Which they are going to do this May. A new proton beam will be generated and I can guarantee
you, all sorts of people are going to be involved making independent measurements to verify
the OPERA result.
But, as far as I'm concerned, it's already looking bad for the idea that something can
go faster than light, which really should come as no surprise. After all, like the Linux
operating system, relativity just works. Time and again it proves its worth.
Well, that's it for this week Space Fans, thank you for watching, and Keep Looking Up.
Now I know I talk a lot about gravitational lensing here on Space Fan News, but usually
it's a galaxy or cluster of galaxies doing the lensing.
And when I talk about microlensing, there's usually a black hole or a star acting as the
lens.
But this week, Hubble has observed quasars that are amplifying and distorting images
of galaxies that lie behind them.
Here's an example. What you see here are three different galaxies taken from the Sloan Digital
Sky Survey and embedded deep within each one is a quasar at the core. In each one you can
see the light from an even further and distant galaxy that lies way behind the foreground
galaxy containing the quasar, which is distorted into these funky little arcs.
This is the gravity of a quasar bending that distant light and forming it into a partial
ring.
As you know, gravitational lensing is pretty common, we see it everywhere, especially in
galaxy clusters where one galaxy is almost guaranteed to be in the way of another within
our line of sight. But this is the first time lensing has been seen from a quasi-stellar
object.
These quasars are supermassive black holes lying at the centers of these galaxies, they
are hundreds of millions to billions of times larger than stellar sized black holes, so
it makes perfect sense that they could be lenses. It takes highly massive objects to
make the kind of gravity necessary to bend light like this.
Now one really handy use of these quasar lenses is that it allows us to actually get the mass
of the host galaxy. You see, it's hard to measure the mass of a galaxy that a quasar
resides in because they are so bright, they block out all the other radiation from the
stars within that galaxy. Since we can't accurately measure the light, we don't get a good idea
of how many stars are there which means we can't get a good estimate of the mass.
BUT, by measuring these arcs and the amount of distortion created by the lens, we can
get an idea of the mass of the galaxy that created that lens in the first place.
The next step is to build a catalog of these "quasar-lenses" that will allow astronomers
to determine masses for a statistically significant number of quasar host galaxies and then compare
them with galaxies without quasars. This will allow give even more accurate estimates over
time.
Next, NASA releases a new catalog of the entire infrared sky from the Wide-field Infrared
Survey Explorer or (WISE) mission.
WISE was launched on Dec. 14, 2009, for the purpose of mapping the entire sky in the infrared.
It did that in 2010 with much better sensitivity than its predecessors.
It collected more than 2.7 million images taken at four infrared wavelengths, and it
captured everything from nearby asteroids to distant galaxies. Since then, the team
has been processing more than 15 trillion bytes of returned data.
The individual WISE exposures have been combined into an atlas of more than 18,000 images covering
the entire sky - and they looked through each one and found more than 560 million individual
objects. They put those into a catalog listing the infrared properties of each one. Most
of the objects are stars and galaxies, with about equal numbers of each.
And many of them have never been seen before.
WISE also saw a lot of near-Earth asteroids, and it found that there are significantly
fewer mid-size objects than previously thought. It also confirmed that NASA has found more
than 90 percent of the largest near-Earth asteroids.
Oh you infrared portion of the spectrum, where would we be without you?
Next, it turns out the Hubble Space Telescope is better at resolving things that Charles
Messier.
For those who don't know, Charles Messier made a catalog of 110 objects in 1764. He
had a bunch of telescopes, but his favorite was a 7.4 inch reflector that he used to create
his catalog with. He scanned the skies and made note of all the fuzzy patches he saw.
Some of these were galaxies, but he didn't know about those in the 18th century, so he
called them all nebulae.
Over the years, as telescopes got larger, these fuzzy patches became better and better
resolved, culminating in an amazing image of M9, the 9th object recorded by Messier.
Here's roughly what Charles Messier saw.
And here's how that looks under the eyepiece of the Hubble Space Telescope.
This is the most detailed image ever taken of M9. It is a globular cluster, a spherical
swarm of very old stars near the center of our galaxy and lies about 25,000 light years
from us.
Globular clusters harbor some of the oldest stars in our galaxy, born when the Universe
was just a few billion years old. The stars of M9 have a markedly different composition
than stars like our Sun, and they are enriched with far fewer heavier elements.
For example, the elements crucial to life on Earth, like oxygen and carbon, and the
iron that makes up our planet’s core, are very scarce in Messier 9 and clusters like
it. This is because the Universe’s heavier elements were gradually formed in the cores
of stars, and in supernova explosions. When the stars of Messier 9 formed, there were
far smaller quantities of these elements in existence.
Next, what can you do with a giant pair of binoculars named after a sandwich?
Lots of things, but one thing you can do really well apparently is cancel out the blurring
effects of the Earth's atmosphere.
This week, astronomers from the Large Binocular Telescope, or BLT (oh... that's LBT…. never
mind), released the first series of scientific results showing its best-in-the-world performance
in canceling out that blur.
Those were the words they used: "Best in the world".
Located on Mt. Graham in southeastern Arizona, the LBT sports two giant 8.4 meter mirrors
(that's 27.5 feet). It has two of those…
But the cool part is in the secondary mirrors. These mirrors vibrate and bend really fast
to cancel out the distorted wavefronts caused by starlight traveling through a turbulent
atmosphere. As the starlight hits the upper part of our atmosphere, the distorted wavefront
of that incoming light is measured and then - in the time it takes the light to go from
the top of our atmosphere to the ground - a canceling waveform is calculated which bends
the secondary and removes the distortion before the light hits the telescope.
It's called adaptive optics and to ground-based telescopes it is just like downtown because
it lets them get the same results that only a telescope in space can get.
And apparently, no one is better at doing that than the BLT - that's LBT. Oh great,
now I'm hungry.
Finally, using the original neutrino beam used back in September by the OPERA experiment,
the ICARUS team have announced that their findings of the arrival times of neutrinos
blasted from CERN are within the speed limits set by relativity.
The ICARUS experiment was another effort that used the same beam that OPERA used, but it
had a different and independent timing source. Well, they released this week that their results
don't contradict Einstein, they were all well within the speed limit.
Remember, I last reported to you that the GPS timing signals used by OPERA that were
piped underground were found to have faulty connections, making the timing used in OPERA
more than a little suspect, so they need to do it again.
Which they are going to do this May. A new proton beam will be generated and I can guarantee
you, all sorts of people are going to be involved making independent measurements to verify
the OPERA result.
But, as far as I'm concerned, it's already looking bad for the idea that something can
go faster than light, which really should come as no surprise. After all, like the Linux
operating system, relativity just works. Time and again it proves its worth.
Well, that's it for this week Space Fans, thank you for watching, and Keep Looking Up.