It’s becoming increasingly clear that there is alien life out there, in our solar system and beyond. To the extent that people still cling to the geocentric notion that Earth is the only planet in the universe capable of supporting life, it’s time to think again.
The latest indicator of that reality came yesterday, when NASA announced that its Cassini spacecraft had found promising signs that alien life may exist on Enceladus, one of the moons orbiting Saturn. Cassini flew through a plume that was spraying out of the icy shell covering Enceladus and detected molecular hydrogen. That’s a big deal because molecular hydrogen is created by interaction between warm water and rock, and along with carbon dioxide is the kind of food that early, microbial life forms can thrive on. Scientists believe that life on Earth may have started in the same kind of environment surrounding the deep geothermal vents in our oceans — and if life started here, why shouldn’t it also occur in the same environment elsewhere?
Does that mean that there is, in fact, some form of life already existing on Enceladus? Not necessarily, because the large amount of molecular hydrogen and carbon dioxide detected by the Cassini spacecraft suggests that there isn’t much, if any, bacteria or microbial life on Enceladus actually consuming the food — a fact that doesn’t surprise scientists, because they think Enceladus is relatively young and it takes a long time for life to emerge.
But equally intriguing is that NASA also announced that the Hubble telescope found evidence of similar plumes on Europa, a much older moon orbiting Jupiter. Because Europa has apparently been around for billions of years longer than Enceladus, the combination of molecular hydrogen, carbon dioxide, and time might have allowed life to gain a foothold there. It’s something we’re going to have to explore.
The space-based telescopes keep making amazing discoveries. The latest is the Hubble space telescope’s identification of the most distant galaxy ever detected — a galaxy that is more than 13 billion light years distant from Earth. That means that the light we are seeing now has traveled for 13 billion years to reach our space. In fact, the light we are seeing from that galaxy emanates from stars that blazed only 600 million years after the Big Bang. Those stars almost certainly exist no longer, having long ago gone supernova or turned into one of the other stellar objects that are created when stars die. In that sense, the Hubble telescope is a real-life time machine that allows us to peer into the distant past.
The Hubble space telescope
Astronomers will study the new discovery with great interest, because it may help to provide answers to some very provocative questions. What was the life cycle of early stars, whose intense heat produced the heavy element “star stuff” (to use Carl Sagan’s phrase) of which our universe is made? How did the earliest galaxies form? Why is light from such galaxies visible through the “fog” of hydrogen that should have resulted from the Big Bang?
We can expect more amazing discoveries along these lines as new ground-based and space-based telescopes using new technology come on line and begin to probe the heavens.
If you like science and space, you can do worse than regularly visit the NASA website, just to see the latest information and images posted there. Recently they put up a very interesting depiction of the Crab Nebula, based on combining the Chandra X-ray image (shown in blue), the Hubble Space Telescope optical image (shown in yellow and red) and the Spitzer Space Telescope infrared image (shown in purple). The result is the striking image shown above.
The Crab Nebula is the remnant of a supernova that was first observed in 1054 A.D. and was recorded and marveled at by humans across the world. When the light from the explosion first reached Earth (of course, the explosion itself had happened long before) it was so bright it could be seen in broad daylight. In the center of the nebula is now a neutron star, and if you look carefully at the image you see a fascinating, roiling cauldron of gases and gravitational phenomena surrounding the star. It is no wonder that the Crab Nebula is one of the most studied celestrial items.
The shuttle astronauts upgraded the Hubble space telescope recently, and their work has really paid some immediate dividends. NASA has released a series of very cool photos from the Hubble telescope, which can be found on NASA’s website. The new imaging camera on the Hubble telescope is more sensitive to visible light and also allows the telescope to observe and photograph objects in ultraviolet and near-infrared light.
Starstuff in NGC 6302
The photos include the barred spiral galaxy NGC 6217, which lies more than 6 million light years away, and a particularly evocative picture of the death of a star in planetary nebula NGC 6302, at right. What appears to be the shimmering wings of a stellar butterfly is actually hot gases, blown out of a dying star that was five times the size of the sun and then subjected to ultraviolet radiation. Carl Sagan probably would have called it starstuff. In any case, it is amazing that Hubble can turn out this kind of stunning photographic record of stars, galaxies, and other faraway space phenomena.
The Sun’s slide show presentation of these and other new photos from Hubble –including the way-cool cat’s eye nebula — is highly recommended.