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Infrared Telescope Lifts Off
An anonymous reader writes "On its Delta 2 Heavy-Lift vehicle, the Space Infrared Telescope (SIRTF) successfully launched to its solar orbit at 1:35 AM (EDT). As a result of the expansion of the Universe, most of the optical and ultraviolet radiation emitted from stars, galaxies, and quasars since the beginning of time now lies in the infrared. How and when the first objects in the Universe formed will be learned in large part from this observatory's infrared observations."
Now they can catch me speeding from outer space!
I work at Ball Aerospace... I thought some of you might like to see the BATC stuff.
> So, this means it will be able to see through those bikinis, eh?
First you'd have to spot one among the heavens. Aren't you being a tad optimistic?
Umm, d00d, I think you're supposed to understand that light was in those ranges when it was created, but redshift due to the expansion of space and the massive distances this light has travelled have resulted in it shifting down-spectrum into the infrared.
I posted this as a news story yesterday. It was rejected.
Anyway,
Here's a nice article about SIRTF that I found to be pretty cool.
No, but I am wondering where the 'F' came from.
On its Delta 2 Heavy-Lift vehicle, the Space Infrared Telescope (SIRTF)
Bob : So, uh, whaddya think we should call this thing. I mean, it's just a Huge Infrared Telescope.
Jim : That's brilliant! HIRT! Haha! Everyone will laugh at our clever naming scheme.
Bob : Yeah, but the heads of the program will never go for it. How about SIRT? Space Infrared Telescope?
Jim : Hmm, don't you think 4 letters in an aerospace acronym is soooo cliche? Can't we make it 5 letters or something?
Bob : Sure, let's just add an 'F' to it. Pronounce it "sir tiff".
Jim : Even more brilliant, Bob! I have been looking for something to do my PhD thesis on...maybe I could spend 3 years researching the science behind the formation of aerospace vehicle acronmys...
Or maybe I could just RTFA and find out for my self...
This is great. The more telescopes we can get in orbit, the better. Especially those in different spectrums. There's so much data that the earth is being bomarded wioth constantly that is untapped. We're slowly getting more and more of this data and leaning so much about the universe because of it. I lok foward to the findings of this telescope.
Good health is merely the slowest possible rate at which one can die.
God, I hope they calculate the trajectories right or there might be an interesting "meteor" shower in about 60 years...
CNN Article
They will soon be needing LONG exposure times.
As long as they can point accuratly, it shouldn't be a problem.
Things in space inevitably drift a little, but the beauty of digital cameras is that you don't have to do the exposure all at once. You could pause, re-aim the telescope then begin again.
Well, I suppose you know about the red shift due to the general expansion of the universe? The most distant objects in the universe are now receeding away from us at such a massive rate that the visible light they emitted has been so far red shifted as to wind up in the infrared region. There's a Doppler effect for light that causes light from an object moving very quickly away from an observer to reach the observer at a lower frequency than what was transmitted (the red shift), just like a car moving away from you makes sounds at a lower pitch than were it standing still or moving towards you. Because of Hubble's law, the farther away an object is, the faster it's moving away from us, and consequently, the greater the Doppler effect. This infrared probe is designed to view objects that have been so far "red shifted" as to apparently be emitting infrared radiation.
Qu'on me donne six lignes écrites de la main du plus honnête homme, j'y trouverai de quoi le faire pendre.
Of course, I'm talking about more conventional cryostats. The laser cooling methods that the poster referred to are only relevant for gas phase atoms.
Instead, the telescope launched with 360 liters of liquid helium. It will last 5 years. When the helium is gone, the mission is done. You can read about it here:
His nickname? Ray?
Actually, it can get pretty damn hot with the Sun up there. If the satellite were out of the solar system, then it is true that cooling wouldn't be much of an issue. But, with the Sun right next door (astronomically speaking), it's very important that you have good cooling. In fact, this will only be a 2 year mission, due to the fact that the cooling system (liquid helium, I believe) will only last for that long. . .
I couldn't tell if you were experimenting with poor-man's cryogenics or looking for the orange sherbet.
Space is not cold enough to cool down the elements surrounding the camera so that they are essentially "invisible" to it. If you need evidence, take a look at what happened when the cooling on Hubble's IR cam (NICMOS) ran out prematurely. NICMOS was completely useless until it was serviced rather recently, because it was constantly saturated by the infrared light emitted from the surrounding instrumentation.
I'm no physicist, so I may not have the terms right in my explanation, but you definetely need cooling for IR cams in space. NICMOS will prove it to you.
Technically, space itself is cold around here, yes... but only because there isn't much in the way of matter to heat up. That also means there isn't any physical medium of significance to transfer heat to kinetically, so you can only radiate heat away.
Effectively, this means that if your spacecraft is directly exposed to a radiant heat source like, say, the sun, and you are fairly close to it, you have a serious need to dump heat from the far side if you want to stay frosty.
...the beauty of digital cameras is that you don't have to do the exposure all at once. You could pause, re-aim the telescope then begin again.
Actually, the real beauty of digital cameras is that you can do several images slightly offset from each other and drizzle the light around to get a larger image at a higher. That's how Hubble's big images are done.
Dunno if they're going to do this with SIRTF, though.
Exit, pursued by a bear.
Thanks for all the responses! You've shed a lot of light, on heat.
I'm a writer, a poet, a genius, I know it. I don't buy software, I grow it.
the optical and ultraviolet regions do not lie in the infrared region.
Yeah, but...
Ultraviolet range is anything with a frequency above violet light, optical is the frequencies between violet to red, and infrared is anything with a frequency below red light.
Light that was emitted at an ultraviolet or optical wavelength can be slowed down in frequency - Dopler shift is probably the most well known. Heard of red-shift?
Any frequency - gamma rays to visible, if red-shifted far enough is now infrared, and that is what this telescope is looking for.
The entire statement you selectively quoted is:
As a result of the expansion of the Universe, most of the optical and ultraviolet radiation emitted from stars, galaxies, and quasars since the beginning of time now lies in the infrared. I added emphasis to the important part you left out.
So, while you are pedantically correct in that "Optical (visible?), ultraviolet and infrared are distinct parts of the electronmagnetic spectrum. [T]he optical and ultraviolet regions do not lie in the infrared region.", what was originally said is correct and your post does not correct anything.
By the way, unless you go with a definition of red and violet based on specific wavelengths, the designations "ultraviolet" and "infrared" are subjective, and may overlap with visible light to some extent. I am saying that MY definition of where the frequency gets high enough to no longer be visible and therefore becomes "ultraviolet" may not be the same point for you. It should be relatively close, but almost certainly not the exact same as it is subjective.
Acts of massive stupidity are almost never covered by warranty. --me.
Here are some links to other projects that have similar goals - examining expansion of the universe, faraway objects, etc. They also have sophisticated infrared imaging capabilities. The James Webb Space Telescope (formerly Next Generation Space Telescope) is the successor to Hubble, and Supernova/Acceleration Probe which, from what I remember, locates potential supernovae by examining data taken at fixed ground locations then points an orbiting camera at the calculated location to collect radiation data. Really interesting stuff!
FYI: The longest HST single HST observation I found was a GHRS spectrum at 230,414 seconds. The longest NICMOS (infrared) exposure was 3839 seconds. It's rare to do a single long exposure. Most of the time, exposures are split and stacked, usually to clean out the cosmic rays.
Exit, pursued by a bear.
- "Thick" Java Client for proposals, planning and data retieval - yes folks, Java on the desktop does work
- Estimating and visibility servers - many computing drone managed by a J2EE server
- Web services access to all of the public data produced by SIRTF - Perl,
.NET, C++ is doesn't matter you can all get the data
Oh, I forgot the mention.... there is not a single Windows box in the operations system. It's all Unix based because... well you know why don't you?Using a simple pumped He3 system, which we just set up in our lab last week, you can easily reach about 300 mK. You use a pumped He4 bath to surround your insert, keeping it at about 1.5 K, and then pump the He3 with a charcoal sorb, to get to 300 mK. In space, you can use blackbody radiation to cool you to the ambient temperature of space (I forget whwat it is, somewhere between 3 to 7 K), and then use He3 pumping to go colder.
You can also get to about 10 mK if you use a dilution regridgerator, which uses a mix of He3 and He4 and relies on changes of entropy as you add them together, and then separate them out.
However, this all assumes that the highest CCD's need to actually go this low. But if for some reason this is needed, these refridgeration techniques are much more efficient and easier than laser cooling. Laser cooling is when you need to go COLD, like microKelvins.
make world, not war
From the CNN.com article:
SIRTF's detectors are incredibly sensitive. If you could put a common household television remote control in deep space SIRTF could detect it at a distance of 25,000 miles.
Considering that taxpayers put up 1.9 billion for the observatory, do you think they could use it to find the remote cotrol that I lost in my living room?
It is worth noting that the SIRTF SWIRE survey may be able to detect solar system sized supercomputers, aka Matrioshka Brains. For discussion see the thread starting here and navigate using the icons in the upper right hand corner of the screen.
reminds me of a conversation I had with a friend many years ago that we still laugh about...
him: if you had an infinitely small aperature, you could take pictures with infinite depth of field!
me: but you'd have to take an infinitely long exposure...
him: not if you had infinitely fast film!
-calyxa
Decay! Decay! Decay! -Helium
Wrong. The long distances do matter a lot. The main reason far away objects seem to be speeding away from us is that the space between has been expanding in size. A photon traveling through this expanding space also stretches, and the further it has to go the more it stretches. Doppler has nothing to do with it.
"I'm so moist I'm sticking to the leather." -Kermit the Frog on The Late Late Show
Around any pair of orbiting bodies are what we call the Lagrange points... points of relative stability where gravitational forces balance out.
L2 is, I believe, opposite the Sun on the other side of earth... I am unsure if it would be in shadow, as I'm not sure of the distance... but something sitting there will have a year the same length as the earth.
This is due to the earth's gravity added to the suns.. effectively something at L2 feels like it's orbiting a heavier mass, so it can orbit faster to keep up.
There are four other lagrange points... one towards the sun (where the SOHO solar observation satellite lives), (L1)
One on the opposite side of the Sun from us (always behind the sun from our point of view, so that's where the hidden planet X is)
And two ahead and behind our orbit, sort of (google up a diagram). these are sometiems called "Trojan points"... asteroids are found orbiting these points by Jupiter, Mars... not at earth, though large concentrations of dust have been found gathered there.
Indeed. The Hubble Deep Field images were assembled in exactly this way.
By the way, the parent post is modded Funny. Why is that?
~Idarubicin
SCUBA (Submillimeter Common-User Bolometer Array) on JCMT maintains a temperature of about 60mK using a liquid helium dilution refrigerator. It is probably the continuously coldest place that we know of in the universe, since it maintains 60mK for weeks on end.
So no, you don't need laser cooling techniques to get down to these low temperatures for astronomical detectors.