I saw a good example of the “light pollution” as I flew into Newark on a clear night earlier this week. Ironically, the light from the houses, parking lots, and shopping centers on the ground reminded me of the stars and constellations of the evening sky.
Science continues to achieve amazing advances in our ability to detect, measure, and analyze planets orbiting stars far outside our solar system.
So far, scientists have discovered and confirmed the existence of more than 800 planets. Most of the planets, however, are huge gas giants, like Jupiter or Saturn in our solar system. The latest advance in detection capabilities came this week, when scientists announced that they have detected the lightest planet to orbit a Sun-like star — and the star just happens to be Alpha Centauri, a weird, triple-star system that is the Sun’s nearest galactic neighbor.
Alpha Centauri, for those who fell asleep during astronomy class, is a mere 4.3 light years away. Of course, one light year is 6 trillion (6,000,000,000,000) miles away, but who’s counting? The planet scientists have detected is about the mass of our good Earth.
Before you start worrying that little green men might appear on your doorstep tonight, take a deep breath: the Earth-sized planet is closer to Alpha Centauri B than Mercury is to the Sun, so it’s probably not conducive to life. Still, the discovery is remarkable. In the not too distant future, scientists will use this detection technology to find a planet about the size and mass of Earth, orbiting a star a lot like Sol, at a distance that would suggest that it is likely to be temperate. What will that mean? My guess is that we will train every radio telescope and sensory device we have in the direction of that planet, listen as hard as we can, and hope.
Venus is on the move today and tomorrow. It’s traveling slowly across the face of the Sun, on a journey that astronomers call being “in transit” — as if Venus were hopping a subway to get from one side of the solar system to another.
These kind of astronomical events are very cool, because they happen so rarely. There’s a “music of the spheres” sort of celestial harmony to Venus’ journey that reflects a special, highly unusual confluence of positioning of the Sun, Venus, and Earth. It won’t happen again for 105 years. By then, we hope, the European debt crisis will have been resolved. In fact, some astrologers are saying that the transit of Venus might help to solve such problems. It’s is supposed to herald in a new era of spiritual and technological revolution . . . or, it’s supposed to strongly accentuate feelings of love and hate. With astrology, it always seems to be one or the other.
As with any solar celestial phenomenon, the news stories always caution people not to look directly at old Sol. It’s hard to believe anyone would try to use the naked eye to check out the Venus transit, because Venus will be only a small speck against the enormous disk of the Sun. You supposedly can see it safely by creating one of those pinhole-in-a-box projectors that the news stories typically mention in these circumstances. I tried to make one of those devices when there was a solar eclipse during my childhood, and I gave up in frustration when it didn’t work. This time, I’ll just rely on the photos, and in the meantime wish Venus well on her cross-town travel.
The universe began with the Big Bang billions of years ago, and now astronomers say we’ll be dealing with another big bang — in about four billion years or so.
The coming big bang will occur when our galaxy, the Milky Way, collides with and merges into Andromeda, a neighboring galaxy. The two galaxies are being pulled together by their mutual gravities, and in fact are rushing toward each other at the breathtaking speed of 250,000 miles per hour. At such astronomical (pun intended) speeds, it’s hard to believe that all Earth-dwellers aren’t experiencing a touch of cosmic motion sickness.
Of course, galaxies are mostly empty space, so whoever is left on Earth when the galactic convergence occurs isn’t likely to see suns and planets smashing into each other. But the night sky will look different. Orion and Taurus and Ursa Major will have lots of company.
Continuing developments in telescope technology are causing astronomers to increase their estimates of the number of Earth-like worlds in the universe.
The latest disclosure deals with the existence of “red dwarf” stars, which are dimmer and smaller than the Sun. Until recently, telescopes have not been sufficiently powerful to detect such stars in other galaxies. Enhancements to telescopes, however, have allowed astronomers to determine that red dwarf stars are far more common than was previously suspected. Indeed, astronomers believe that such stars are 20 times more prevalent in older galaxies than in our galaxy. As a result, astronomers also are concluding that there likely are many more Earth-like planets orbiting those stars — possibly trillions of Earth-like worlds.
Trillions of Earth-like planets? The concept is provocative, because increases in the number of planets logically also increases the likelihood of life, and therefore intelligent life, on at least some of those faraway planets. And the follow-up question is even more provocative: would the existence of intelligent extraterrestrial life be good or bad? Would we rather be the only intelligent life forms in the universe, or would we prefer to learn that we are not alone — indeed, that intelligent life is as common as the fish in the sea? How comfortable would humans be with the knowledge that they live in a crowded neighborhood, where neighbors might drop in for a visit at any moment?
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.
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.