Friday, June 08, 2007

M81 in Three Bands


Atlantis lifted off at 7:38 PM EST on a planned 11-day mission. These are old spacecraft, which makes one concerned for the crew's safety. Like the 1960's families who gathered around the TV set for every launch, we will ignore the media's fixation on suicide bombing heiresses and watch 7 people try to make a difference. I will delay my announcement about spaceflight until after they have returned safely.

A shuttle has many thousands of parts, any one of which could fail. The engines are pressurised via 24 spherical tanks filled with helium or nitrogen. The tanks are made of metal wrapped in kevlar, and must contain pressures up to 4600 psi. Failure of one of the tanks would be catastrophic. In 1988 the tanks were certified for an additional 10 years use. Since then the tanks' manufacturer has gone out of business. Two more flights to go for Atlantis, whose last flight will be the Hubble servicing mission scheduled for September 10, 2008.

One more three-colour picture for the week. Galaxy M81 in Ursa Major seen in infrared by the Spitzer Space Telescope (red), in visible light by Hubble (white) and in ultraviolet by the Galaxy Evolution Explorer. The youngest stars, seen in blue, line the galaxy's edges while older stars cluster near the centre. Interstellar dust appears in red. Hidden even from these eyes is a halo of "dark" mass, detectable only by its gravitational influence.

At the centre of this and every other galaxy is a supermassive Black Hole. Singularities were formed from quantum fluctuations shortly after the Big Bang. Giant Black Holes formed the seeds of clusters, galaxies and even smaller structures. Smaller Black Holes were attracted by the big ones and formed haloes around the galaxies. The matter we see is only a fraction of what is out there.

Check out the new Carnival of Space!

UPDATE: As this is published, a 3.5 inch hole has been found in Atlantis' thermal blanket. The fault has been judged to be non-critical and the mission goes on.

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5 Comments:

Blogger mark said...

beautiful photo!

re:the space shuttles: scary--really have to move on from these things

3:10 AM  
Blogger nige said...

Yes it is scary. I remember watching the launch of Challenger live on TV in 1986 with my mum, after school on a weekday (London time).

The TV commentators were saying the crew would had a chance of survival in an escape pod?

I know Apollo rockets had an escape pod at the top that could save the astronauts in case of certain types of explosion, but not the shuttle?

It is a scary to watch live TV of shuttle operations now they are so old and have so much to potentially go wrong.

Hope they get back safely with that hole in the thermal blanket.

4:58 AM  
Blogger L. Riofrio said...

No escape system. Columbia had two ejection seats for Young and Crippen's first flight in 1981. Those were later removed and would not have helped in 2003 because the shuttle came apart at 200,000 feet. Orion will go back to the escape tower.

6:17 PM  
Blogger Stephen said...

I looked at M81 just the other night from my driveway. My driveway faces a grocery store parking lot, with attendant flood lights. I call it my Mercury Vapor Observatory (MVO). Since my driveway is essentially in Detroit, you could call it a bright spot.

M81 and M82 fit in a low power field. If you can see the full moon in your field of view, you can see both of these galaxies. They're easy to tell apart, since M81 is kinda face on showing a disk, and M82 is edge on, like a line.

It shouldn't be a surprise that space based observatories yield more detailed views. HST alone cost six orders of magnitude more than my scope.

5:08 AM  
Anonymous a quantum diaries survivor said...

Hi Louise,

I also had the privilege of seeing M81 through some glass. It is a beautiful galaxy, but its splendor is only apparent under dark skies, when a 16" class instrument as mine does not fail to show the arms, which encircle the central bulge.

On a different note: I have been assigned a master thesis to review for our graduation session of June 27th. It is a study of a gamma source -3EG J1835 +5918 - with the MAGIC telescope. Once I've read it I will let you know whether there is evidence for a black hole inside!

8:16 AM  

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