Space Fan News #64: Introducing SOFIA; Nibiru Can't Hide; Overfed Black Holes


Uploaded by tdarnell on 11.05.2012

Transcript:
Hello Space Fans and welcome to another edition of Space Fan News.
You know, I don't think I've ever told you about SOFIA. SOFIA stands for Stratospheric
Observatory for Infrared Astronomy and it's this really cool infrared telescope that operates
in the fuselage of an old Pan Am 747 - the Clipper Lindbergh I think - that has been
basically rebuilt from the ground up.
Like it's name says, this is an infrared telescope and is a whopping 2.7 meters across (that's
almost 9 feet). It's mounted towards the rear of the specially modified Clipper.
Observations are done at altitudes of up to 13,700 meters at speeds of about 800 kilometers
per hour by opening this huge door towards the rear of the airplane.
One would think that it would be difficult to get clear images under these conditions,
but they have mounted this telescope in such a way that it is as stable as if it were sitting
on a mountaintop. There's also a special deflector that directs the airstream away from the optics
and the telescope mount.
One limitation is that because it is flying around, the longest it can look at an object
is a few hours.
So this telescope is very interesting in many ways, and is a relatively cheap way to get
above the atmosphere so that we can get good infrared observations.
This mission has been in the planning, building and testing stages for many, many years and
it has finally returned it's first science results this week.
Using the GREAT instrument (no that's not a comment on how great it is, it's an acronym)
which stands for the German Receiver for Astronomy at Terahertz Frequencies (I know, they really
stretch with these acronyms sometimes) - astronomers have detected the velocity signature of infalling
gas in the envelopes of three protostars, directly probing the dynamics of a forming
star.
GREAT is designed specifically for studies of interstellar gas and the stellar life cycle,
from a protostar's early embryonic phase when it is still embedded in its parental cloud
to an evolved star's death when the stellar envelope is ejected back into space.
Detecting these gas inflows was a sign that GREAT, and by extension SOFIA, are doing what
they were designed to do and that there's a bright future (no pun intended) for this
really cool observatory.
I'll make sure to keep you up to date on any future discoveries.
Next, astronomers are getting really clever about how to find planets around other stars
we can't see.
By now, you are all very familiar with the Kepler Space Telescope, which is looking at
150,000 stars in the constellation Cygnus and measuring tiny dips of brightness as a
planet passes between us and the star.
While this technique is accurate and enables us to find planets around other stars, it
is biased towards finding only those planets that pass between us and the star. If the
star doesn't have an orbit that's oriented so that it gets in the way, well we're out
of luck, we won't be able to detect it.
But hold on a minute. Using the same theory that French mathematician (please forgive
my pronunciation) Urbain Le Verrier used to predict the existence of Neptune based on
small deviations in the motion of Uranus, astronomers have found a planet around Kepler
Object of Interest 872.
Turns out that KOI 872 has a transiting planet - planet b - that had already been measured
by Kepler, but it had strange time variations over the two hours it transited. According
to astronomers, It quickly became apparent that a large hidden object must be pulling
on the transiting planet.
So, using the Le Verrier perturbation theory and lot of computers to run through many possible
planet configurations, they determined that there was a planet about the size of Saturn
pulling on planet b and it orbits the host star every 57 days.
They are calling - not surprisingly - planet c. That's little c - it matters.
And it never passed between the star or us.
And we found it anyway.
Just like downtown.
Finally, we have some more Herchel news. The Herschel Space Observatory has shown that
galaxies with the most powerful, active black holes at their cores produce fewer stars than
galaxies with less active black holes. These results are the first to show that black holes
suppressed galactic star formation when the universe was less than half its current age.
It's always been puzzling to astronomers why there weren't more stars than there are. If
you run simple models forward, you always get more stars, but we don't see that. One
idea is that supermassive black holes suppress star formation in galaxies.
So, naturally, astronomers are very interested in finding out how star formation and black
hole activity are linked.
What may be happening is that these hyper, central black holes likely heat up and disperse
the galactic reservoirs of cold gas that are needed to create new stars. Most studies have
only provided snapshots in time, leaving the overall relationship of active galactic nuclei
and star formation unclear, especially over the cosmic history of galaxy formation.
This study by Hershel is more comprehensive over a longer period of the universe's history.
Here, they used Herschel data that looked at 65 galaxies at wavelengths in the far-infrared.
These wavelengths are ideal for this because they reveal the rate of star formation, because
most of the energy released by developing stars heats surrounding dust, which then re-radiates
out in far-infrared wavelengths.
Then they compared their infrared readings with X-rays that were coming from the active
central black holes in the galaxies, using NASA's Chandra X-ray Observatory.
So things bright in the far infrared meant stars were forming and they were compared
with active black holes which are bright in X-rays.
What they found is at lower intensities, the black holes' brightness and star formation
increased in sync. However, star formation dropped off in galaxies with the most energetic
central black holes.
Astronomers think inflows of gas fuel new stars and supermassive black holes. But feed
a black hole too much, and it starts spewing radiation into the galaxy that prevents raw
material from coalescing into new stars.
Well, that's it for this week Space Fans, thank you for watching and, as always, Keep
Looking Up!