In approximately one year's time, NASA will launch its next major space observatory, an infrared telescope called SIRTF -- the Space Infrared Telescope Facility. In this day and age, it goes without saying that the new space telescope is expected to revolutionize our view of the universe. Technology is simply advancing at such an amazing rate that every new telescope we put up can't help but be hundreds, if not thousands of times better than its predecessors.
But somehow that isn't enough for NASA. To the public, distant satellites floating around in space can seem very remote, very disconnected from our lives. To combat this feeling of isolation from science, NASA needs your help. The public is being called upon to name the new space telescope.
In my mind, it's never a good idea to name something before you actually get to know it a little. So what is SIRTF all about? How is it expected to change our view of the universe? And, to be candid here, why does NASA need another space observatory when the ones they already have are working just fine, thank you very much? To begin with, SIRTF is part of a larger family called NASA's Great Observatories. Other members you may have heard of are the Hubble Space Telescope, the Chandra X-Ray observatory, and the Compton Gamma-ray Observatory. These four observatories were designed to complement each other in quite an interesting way: each looks at the universe using a different kind of light.
But what does that mean, using different kinds of light to look into space? When you look at a gorgeous, full-color picture of a galaxy from the Hubble Space Telescope, you can see all the colors of the rainbow, all the colors the human eye can see. What other kinds of light are there? The other three members of NASA's Great Observatories are designed to look at the universe in invisible light: light the human eye can't sense. For a lot of people, the idea of invisible light seems new and unfamiliar. It shouldn't.
By now we've all been warned to slather on sunscreen when we go outside. We're not protecting ourselves from visible light, which doesn't damage our skin, but from ultraviolet light. Ultraviolet is a kind of light that our eyes can't sense, but our skin definitely can as it gets burned. This sort of light carries more energy than visible light, and can cause more damage when it hits us.
How about X-rays? That's a kind of light that packs so much energy, it goes right through our bodies, allowing a look inside. Everyone on the planet is familiar with infrared light, but we tend not to think of it as a sort of light. Instead, we sense it as heat. That's why night-vision goggles often see in the infrared: even in complete darkness, you can't hide your own body heat. Another way of saying it is that in infrared light, a human body naturally glows, as clearly as a light-bulb in a dark room. It's just a kind of light our eyes can't see.
We call all the different kinds of light electromagnetic radiation, as all forms of light, invisible or not, are made up of electrical and magnetic fields which are bound together into a package called a photon. And photons can carry different amounts of energy. In visible light, for example, we perceive different energies as different colors. A photon of blue light has more energy than green, which has more energy than yellow, so on and so forth all the way down the rainbow. The lowest energy light the human eye can see is red light. The next "color" down is infrared (which literally means "beneath red"), which we can't see at all, but can perceive as heat.
Using all these different observatories gives us a much more complete view of the universe. There are plenty of things out in space that don't radiate any visible light, making them completely undetectable to a visible light telescope, like the Hubble. Take planets for instance. Planets like earth are just small chunks of rock orbiting a star. Sure, we may reflect some sunlight (like the moon does), but for the most part, we don't emit any visible light. If astronomers on another planet light-years away from us were looking down at our solar system, they would never be able to detect the tiny amount of visible light coming from earth. But what if they looked in infrared light? The earth is quite warm (roughly human body temperature), which means that it glows, actually gives off its own light, in infrared.
The idea of temperature is really important when you talk about different kinds of light. The hotter an object is, the higher energy light it can give off. Take the sun for an example. The sun is about 6,000 degrees, and can obviously give off relatively energetic kinds of light like visible and ultraviolet. A person, in comparison is only about100 degrees. Instead of glowing in visible light, we give off heat, or infrared light. What about something hotter than the sun? Some of the most energetic objects in the universe, like the explosion of a dying star or gas caught in a tight orbit around a black hole, can reach temperatures of billions of degrees. What kind of light would that sort of object emit? That's the realm of gamma rays and X-ray, the most energetic forms of light.
And that, in a nutshell, is what the Great Observatories are all about. The Chandra X-ray observatory, for example, can only see objects that are millions of degrees hot. It studies titanic explosions, colliding neutron stars, anything that makes a really big boom. That's a very different view of the universe than an infrared telescope would see, where warm planets or the hearts of star-forming interstellar clouds would dominate the sky.
And getting back to infrared telescopes, those are just some of the things that SIRTF is setting out to study. Although SIRTF will not be able to take pictures of individual planets around other stars (NASA is designing telescopes to do that in the near future...), it will be able to detect the warm dust left over from planets formation. In essence, SIRTF will be able to detect when planets exist around another star, even if it can't image them.
A large census is planned, which should uncover hundreds of new solar systems. SIRTF will also be able to peer into giant clouds of dust and look for the first signs of star birth. Long before a star turns on and begin to shine (at least in visible light), it slowly heats up inside a cocoon of dust. For the first time, we'll watch the whole process of star and planet formation.
On a completely different scale, infrared light will allow us to peer farther out into the universe than any visible light telescope can. As light travels through the expanding universe, it loses energy. In visible light terms, we watch light become more and more red-colored as we look farther out into space (this effect is called the "red-shift" by astronomers for that very reason). At some point, when you look billions of light-years away, all the visible light gets red-shifted away. How do you look farther than that? The light of distant galaxies may have been shifted out of our visible range, but it's still there in infrared. You can actually see farther out into space using an infrared telescope.
From nearby stars and their surrounding planets, to the very edges of the known universe, SIRTF will give us a view of the sky never seen before.
Sound good to you? Want to be a part of it? By going to SIRTF's main web page, sirtf.caltech.edu, you can suggest a name and submit a short essay about your choice. Be sure to read the rules and regulations, as some names are off-limits. The contest ends in December, so don't delay too long -- the rewards are worth it. The person with the winning entry will not only get to put a new name in space, but will also attend SIRTF's launch from Cape Canaveral in Florida. How's that for feeling more connected?