There has been a lot in the media about the planetary system found recently around the star TRAPPIST-1. That’s the small dwarf star with seven terrestrial planets that were announced in February. Terrestrial planet just means smaller and probably rocky.

Given that the star is only 40 light years away, it’s virtually in our backyard. But still it is small. It only has about 11% the radius of our own Sun. It was only discovered back in 1999 and was given an unpronounceable alpha-numeric designation. There’s no real hope of an amateur astronomer being able to find it. But this very smallness made it easier to find small planets. (And despite the way we might feel Earth is a pretty small planet.)

The TRAPPIST telescope watched for transiting planets; that is it looked for the tiny change in brightness caused by a planet getting between us and this star. Given that TRAPPIST-1 is so small, it made it possible to see small planets as they crossed the star, in fact, seven of them. Using additional information, the scientists were able to determine estimates of sizes and orbits for all seven. And all seven appear to be small rocky planets. Three of them are orbiting in the zone around the star where we could count on water being liquid, if it is there.

The scientists studying them haven’t been able to look at the atmospheres yet, but that could come as early as next year when a new orbiting telescope (The James Webb Space Telescope) is to be launched. With that new telescope we should be able to learn what kind of atmospheres those planets may have and water vapor might be there.

Given that we only have a sample of one (so far) planet with liquid water, we can’t be too optimistic about finding life on one or more of those planets around TRAPPIST-1. It’s certainly possible.

But these would certainly be strange worlds if they do. All seven of the planets are orbiting very close to their star; closer than Mercury is in our own Solar system. At that distance each of them is likely to be tidally locked which means that they have only one side that faces the star and the other points away so there is no changing from day and night.

So if people of some sort live out there, their world would be very alien to us. As Shakespeare observed, “O brave new world That has such people in’t!”, I’d like to get to know about them. As Mark Twain said, “Broad, wholesome, charitable views of men and things cannot be acquired by vegetating in one little corner of the earth all one’s lifetime.”

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