Are We Alone?
Last updated 10/6/2022 at 12:08pm
Who among us has never gazed into a starry night sky and wondered, "Are we alone in the universe?" With the hundreds of billions of stars in just our own Milky Way galaxy – with possibly trillions of other galaxies beyond – is it not possible that orbiting some stars there are at least a few planets where life has originated and evolved?
The question has been pondered and debated for millennia. In a letter to Herodotus, the ancient Greek philosopher Epicurus wrote: "...there are infinite worlds both like and unlike this world of ours... we must believe that in all worlds there are living creatures and plants and other living things we see in this world."
But it wasn't until 1995 that Swiss astronomers Michael Mayor and Didier Queloz made an announcement that rocked the astronomical community – enough to earn them the 2019 Nobel Prize in Physics.
They reported that the sunlike star 51 Pegasi – affectionately known to astronomers as 51 Peg – some 50.9 light years away appeared to be wobbling as if a planet were orbiting nearby and tugging gravitationally on it. Originally named 51 Pegasi b, this world is now called Dimidium, the Latin word for "half", because it is believed to contain nearly half the mass of Jupiter.
Astronomers calculate that this alien world orbits its parent star in only 4.2 days and that it endures a temperature of some 1,850 F (1,011 C). While a few worlds had already been reported to be circling pulsars – and even a few technical glitches masqueraded as planets – astronomers cite this as the first detection of a planet orbiting an ordinary star.
As of today, astronomers have found 5,159 such exoplanets. And just this year, the James Webb Space Telescope not only photographed the first planet orbiting the star HIP65426 but also found carbon dioxide in the atmosphere of a planet orbiting the star WASP-39.
But 51 Peg will always be special since it was our first. Not only that, but it's a star that backyard stargazers can see easily.
This week, go outdoors after dark and look midway up in the eastern sky. There you should spot the four stars outlining the Great Square of Pegasus. With the accompanying map in hand, identify its shape and some of the stars that make it up.
If your sky is dark and relatively free from light pollution, try to spot 51 Peg. It's located almost midway between the two westernmost stars of the square, and slightly west of the line connecting them.
It's a faint star, barely visible to the naked eye, but you should have little trouble spotting it with binoculars. Don't expect to see its planet, though; that's a feat reserved for today's most sophisticated telescopes.
Whether 51 Peg b – or any other exoplanet – is inhabited is unknown. What is clear, though, is that the chemistry for life as we know it is found everywhere in the universe, and the number of planets where life might form and evolve is increasing every day.
Yes, the question, "Are we alone?" is quite profound, with only two possible answers: yes or no. And each is staggering in its implications!
Visit Dennis Mammana at dennismammana.com.