Space Fan News #71: Early Spiral Galaxy Found; Sharpest Quasar Image; Pioneer Anomaly Solved
Uploaded by tdarnell on 20.07.2012
Transcript:
Hello Space Fans and welcome to another edition of Space Fan News.
This week, astronomers using the Hubble Space Telescope have observed a spiral galaxy.
Now, if I just stop there, you'd be like, 'So what? Hubble observes spiral galaxies
all the time'.
That's true, but this spiral galaxy is from the early universe, and is being observed
as it existed three billion years after the Big Bang.
Again, you might say, 'So what? Hubble sees that all the time too.'
That's true too. But not spiral galaxies and not this early. This galaxy isn't supposed
to exist yet. Spiral galaxies like the ones we see all over the place in the universe
today didn't start forming until much later in the history of the universe. Or so everyone
thought.
The galaxy is known as BX442 and was first observed by Hubble while it was doing a survey
of some 300 galaxies and what's remarkable about it is that it shouldn't exist, at least
not yet.
The first galaxies that ever formed in the universe aren't like the ones we see today.
They were clumpy and irregular and basically a mess. Astronomers who look at these old
galaxies all the time are used to seeing little structure.
So they were quite surprised to see a beautiful spiral galaxy from this period in the universe's
history. It is larger than usual as well compared with galaxies from this time period; only
about 30 of the 300 galaxies they looked at were as massive as this.
After they found it, they didn't believe it at first and took another look using an instrument
with the coolest acronym ever: the Keck's OSIRIS spectrograph.
OSIRIS stands for OH-Suppressing Infrared Imaging Spectrograph and was used to verify
that it was spiral and not some illusion of something like two unrelated disk galaxies
in the same line of sight.
OSIRIS confirmed that not only is it a spiral galaxy, but they also made a series of observations
over thirteen nights to measure it's rotation.
What also sets BX442 apart from other galaxies of its epoch is that it appears to be in the
process of merging with another galaxy. That, in fact, could be the reason it is beginning
to form a spiral.
Many of the most well-known spiral galaxies in the nearby universe (e.g., M51, M81, M101)
are all observed to have nearby companions, and small satellites such as the Sagittarius
dwarf galaxy may even be partly responsible for producing spiral patterns in our own Milky
Way galaxy.
So astronomers are excited about this discovery because BX442 represents a link between early
galaxies that are much more turbulent and the rotating spiral galaxies that we see around
us today.
This galaxy may highlight the importance of merger interactions at any cosmic epoch in
creating grand design spiral structure. Grand design is what they call the well-defined
spiral galaxies in our current epoch.
Next, using radio telescopes around the world, astronomers have taken the sharpest image
of a quasar ever. Pointing the APEX telescope in Chile, and two others on different continents
at the quasar known as 3C 279, they were able to make the sharpest direct observation ever
of the center of a distant galaxy.
3C 279 contains a billion solar mass black hole and it's 5 billion light years away.
They linked the telescopes using something called Very Long Baseline Interferometry,
which makes multiple telescopes act like a single, really big telescope as large as their
separation.
They observed at 1.3 millimeters and got a resolution of 28 micro arc seconds which gave
them ability to distinguish details two million times sharper than what human eyes can do.
With that resolution, they could resolved features less than a light year across on
the quasar, which is amazing for something billions of light years away.
These observations represent a new milestone in imaging supermassive black holes and the
areas around them. Next they want to connect even more telescopes together to create what
they're calling the Event Horizon Telescope, which will enable us to image the shadow of
the supermassive black hole at the center of our galaxy.
The shadow, a dark region against a brighter background, is caused by the bending of light
by the black hole, and would be the first direct observation ever made of a black hole’s
event horizon, the boundary that, once crossed, not even light can escape.
Finally, it's been known for some time that the Pioneer 10 and 11 spacecraft - way out
in the edges of our solar system - are slowing down and it's been really bugging the guys
at JPL. They couldn't figure out why and they called it the Pioneer Anomaly.
Well this week, they figured it out. The Pioneer spacecraft are being slowed down by the heat
from their own instruments.
The heat emanates from electrical current flowing through instruments and the thermoelectric
power supply.
The effect is very subtle, imagine the force of the photons from your car's headlights
pushing you backward as you drive.
Yeah, it's like that.
Launched in 1972 and 1973, Pioneer 10 and 11 are on an outward trajectory from our sun
and in the early 1980s, as the spacecraft were approaching Saturn, navigators saw a
deceleration on the two spacecraft, in the direction back toward the sun. They dismissed
it as the effect of dribbles of leftover propellant still in the fuel lines after controllers
had cut off the propellant.
But by 1998, as the spacecraft kept traveling on their journey and were over 8 billion miles
(13 billion kilometers) away from the sun, a group of scientists at JPL realized there
was an actual deceleration of about 300 inches per day squared (0.9 nanometers per second
squared).
Since they thought they had accounted for everything, some raised the possibility that
this could be some new type of physics that contradicted Einstein's general theory of
relativity.
Well luckily the laws of physics survive to live another day, because they decided to
start gathering records stored all over the country and analyze the data to see if they
could definitively figure out the source of the deceleration.
They did this in part, because they were thinking about proposing a deep space physics mission
to investigate the anomaly, and they wanted to be sure there really was one before asking
NASA for a spacecraft.
So in classic 80's montage form, they went searching for Doppler data, the pattern of
data communicated back to Earth from the spacecraft, as well as telemetry data.
Now, you need to remember, at the time these two Pioneers were launched, data were still
being stored on punch cards. But luckily, there were some digitized files on a computer
at JPL which did the navigation and have helped steer the Pioneer spacecraft since the 1970s.
They also found over a dozen of boxes of magnetic tapes stored under a staircase at JPL and
received files from the National Space Science Data Center at NASA Goddard Space Flight Center,
Greenbelt, Md., and worked with NASA Ames Research Center, Moffett Field, Calif., to
save some of their boxes of magnetic optical tapes. He collected more than 43 gigabytes
of data, which isn't much by today's standards, but that was a lot for back then.
Sounds like it would make a good movie - for Space Fans anyway. They even got the help
of a Canadian programmer who heard about the effort and write a program to read the telemetry
tapes and clean up the old data.
They saw that what was happening to Pioneer wasn't happening to other spacecraft, mostly
because of the way the spacecraft were built. For example, the Voyager spacecraft are less
sensitive to the effect seen on Pioneer, because its thrusters align it along three axes, whereas
the Pioneer spacecraft rely on spinning to stay stable.
Well, that's it for this week Space Fans, thank you for watching and, as always, Keep
Looking Up!
This week, astronomers using the Hubble Space Telescope have observed a spiral galaxy.
Now, if I just stop there, you'd be like, 'So what? Hubble observes spiral galaxies
all the time'.
That's true, but this spiral galaxy is from the early universe, and is being observed
as it existed three billion years after the Big Bang.
Again, you might say, 'So what? Hubble sees that all the time too.'
That's true too. But not spiral galaxies and not this early. This galaxy isn't supposed
to exist yet. Spiral galaxies like the ones we see all over the place in the universe
today didn't start forming until much later in the history of the universe. Or so everyone
thought.
The galaxy is known as BX442 and was first observed by Hubble while it was doing a survey
of some 300 galaxies and what's remarkable about it is that it shouldn't exist, at least
not yet.
The first galaxies that ever formed in the universe aren't like the ones we see today.
They were clumpy and irregular and basically a mess. Astronomers who look at these old
galaxies all the time are used to seeing little structure.
So they were quite surprised to see a beautiful spiral galaxy from this period in the universe's
history. It is larger than usual as well compared with galaxies from this time period; only
about 30 of the 300 galaxies they looked at were as massive as this.
After they found it, they didn't believe it at first and took another look using an instrument
with the coolest acronym ever: the Keck's OSIRIS spectrograph.
OSIRIS stands for OH-Suppressing Infrared Imaging Spectrograph and was used to verify
that it was spiral and not some illusion of something like two unrelated disk galaxies
in the same line of sight.
OSIRIS confirmed that not only is it a spiral galaxy, but they also made a series of observations
over thirteen nights to measure it's rotation.
What also sets BX442 apart from other galaxies of its epoch is that it appears to be in the
process of merging with another galaxy. That, in fact, could be the reason it is beginning
to form a spiral.
Many of the most well-known spiral galaxies in the nearby universe (e.g., M51, M81, M101)
are all observed to have nearby companions, and small satellites such as the Sagittarius
dwarf galaxy may even be partly responsible for producing spiral patterns in our own Milky
Way galaxy.
So astronomers are excited about this discovery because BX442 represents a link between early
galaxies that are much more turbulent and the rotating spiral galaxies that we see around
us today.
This galaxy may highlight the importance of merger interactions at any cosmic epoch in
creating grand design spiral structure. Grand design is what they call the well-defined
spiral galaxies in our current epoch.
Next, using radio telescopes around the world, astronomers have taken the sharpest image
of a quasar ever. Pointing the APEX telescope in Chile, and two others on different continents
at the quasar known as 3C 279, they were able to make the sharpest direct observation ever
of the center of a distant galaxy.
3C 279 contains a billion solar mass black hole and it's 5 billion light years away.
They linked the telescopes using something called Very Long Baseline Interferometry,
which makes multiple telescopes act like a single, really big telescope as large as their
separation.
They observed at 1.3 millimeters and got a resolution of 28 micro arc seconds which gave
them ability to distinguish details two million times sharper than what human eyes can do.
With that resolution, they could resolved features less than a light year across on
the quasar, which is amazing for something billions of light years away.
These observations represent a new milestone in imaging supermassive black holes and the
areas around them. Next they want to connect even more telescopes together to create what
they're calling the Event Horizon Telescope, which will enable us to image the shadow of
the supermassive black hole at the center of our galaxy.
The shadow, a dark region against a brighter background, is caused by the bending of light
by the black hole, and would be the first direct observation ever made of a black hole’s
event horizon, the boundary that, once crossed, not even light can escape.
Finally, it's been known for some time that the Pioneer 10 and 11 spacecraft - way out
in the edges of our solar system - are slowing down and it's been really bugging the guys
at JPL. They couldn't figure out why and they called it the Pioneer Anomaly.
Well this week, they figured it out. The Pioneer spacecraft are being slowed down by the heat
from their own instruments.
The heat emanates from electrical current flowing through instruments and the thermoelectric
power supply.
The effect is very subtle, imagine the force of the photons from your car's headlights
pushing you backward as you drive.
Yeah, it's like that.
Launched in 1972 and 1973, Pioneer 10 and 11 are on an outward trajectory from our sun
and in the early 1980s, as the spacecraft were approaching Saturn, navigators saw a
deceleration on the two spacecraft, in the direction back toward the sun. They dismissed
it as the effect of dribbles of leftover propellant still in the fuel lines after controllers
had cut off the propellant.
But by 1998, as the spacecraft kept traveling on their journey and were over 8 billion miles
(13 billion kilometers) away from the sun, a group of scientists at JPL realized there
was an actual deceleration of about 300 inches per day squared (0.9 nanometers per second
squared).
Since they thought they had accounted for everything, some raised the possibility that
this could be some new type of physics that contradicted Einstein's general theory of
relativity.
Well luckily the laws of physics survive to live another day, because they decided to
start gathering records stored all over the country and analyze the data to see if they
could definitively figure out the source of the deceleration.
They did this in part, because they were thinking about proposing a deep space physics mission
to investigate the anomaly, and they wanted to be sure there really was one before asking
NASA for a spacecraft.
So in classic 80's montage form, they went searching for Doppler data, the pattern of
data communicated back to Earth from the spacecraft, as well as telemetry data.
Now, you need to remember, at the time these two Pioneers were launched, data were still
being stored on punch cards. But luckily, there were some digitized files on a computer
at JPL which did the navigation and have helped steer the Pioneer spacecraft since the 1970s.
They also found over a dozen of boxes of magnetic tapes stored under a staircase at JPL and
received files from the National Space Science Data Center at NASA Goddard Space Flight Center,
Greenbelt, Md., and worked with NASA Ames Research Center, Moffett Field, Calif., to
save some of their boxes of magnetic optical tapes. He collected more than 43 gigabytes
of data, which isn't much by today's standards, but that was a lot for back then.
Sounds like it would make a good movie - for Space Fans anyway. They even got the help
of a Canadian programmer who heard about the effort and write a program to read the telemetry
tapes and clean up the old data.
They saw that what was happening to Pioneer wasn't happening to other spacecraft, mostly
because of the way the spacecraft were built. For example, the Voyager spacecraft are less
sensitive to the effect seen on Pioneer, because its thrusters align it along three axes, whereas
the Pioneer spacecraft rely on spinning to stay stable.
Well, that's it for this week Space Fans, thank you for watching and, as always, Keep
Looking Up!