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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."
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.
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 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.
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.