The ways of pop science and the misconception of astronomy in the general population are often scary things. All over the internet, magazines, news and people are touting the discovery of “a new Earth”. I think most people believe NASA has a big telescope and they can actually see these planets out there, all blue and green with little Na’vi running around.
What NASA does with the Kepler scope is measure for very slight changes in a star’s spectrum caused by gravital fluctuations that MAY indicate the possible presence of a planet. They don’t actually see anything. On the basis of those fluctuations, they guess the planet’s density, distance from its star and what it’s made of. So they may have found a roughly Earth-sized planet in a star’s Goldilocks zone, and now we have “a new Earth”? In truth, we know absolutely nothing about this planet. For astronomers, it exists as just a set of numbers indicating something orbiting another star.
Let’s pretend this planet is really a new Earth, complete with forests and deserts and an oxygen-nitrogen atmosphere that could support human life. It is 500 light years away. Thanks to goofy sci-fi shows like Star Gate and Star Trek, people think that’s no big deal. I remember in the last Trek movie how the Enterprise zipped to the home world of the Klingons and back as if it was making a run to the corner store. And I’ll never forget a line in the old Star Gate series:–and if you have the background in astronomy that I do, it is very significant–”We’ve detected a distress signal. It’s just 60 light years out of our way. We’re going to swing by and check it out.” It was one of the stupidest statements ever made on television. They acted like 60 light years was 60 miles down the road.
The general public has so little comprehension of the immense vastness of space and the universe. A single light year is vast beyond comprehension. Using modern technology, it would take about 2,500 years to travel one light year. So to get to that “other earth”, a voyage of 500 light years, would take 1.25 million years. For us, for all intents and purposes, that planet doesn’t even exist.
But the simple fact is we have no idea what is actually there. You see, we have two other Earth-like planets in our own star’s Goldilocks zone. Mars is a bit smaller than us and daytime temperatures at its equator can reach 72F. But Mars has a low density core, a fraction of Earth’s gravity, and a carbon dioxide atmosphere too thin to breathe even if we could. It is a cold, dead world.
Venus is virtually Earth’s twin in size and gravity. But Venus has an atmosphere of carbon dioxide that caused a runaway greenhouse effect that long ago killed its oceans. Now it rains sulfuric acid on Venus and the planet has a surface temperature of 900F, hot enough to melt lead.
Odds are astronomically high that that “other earth” out there is just another cold, dead, or baked, dead rock just like the frozen hell or the hot hell that orbit our own star. Earth is alive. Earth is a rare, breathing, teaming jewel in a stark universe.
I hate these pop science misconceptions because they give the impression there are many other worlds out there, and when we mess this one up bad enough, we can just jump ship. They cheapen our Earth. Earth is our home, likely the only home we will ever have, the only place in this vast universe we are suited to live or that we will ever reach. She is not replaceable.