Yesterday’s NASA announcement about the discovery of 7 Earth sized exoplanets in the Trappist-1 system is all over the news. People seem understandably excited, and even Google celebrated creating a brand new doodle just hours after the announcement. And as usual with scientific news, you can find quite a lot of confusion around.
So what does a discovery like this actually mean?
It means that astronomers have found strong evidence of the existence of those 7 planets orbiting a star other than our own. They have a pretty good idea about their size and mass and where they are and a bunch of other things, but… they don’t have any cool pictures of them! Sorry to disappoint on that one 🙂 This is probably the most common confusion I’ve seen, and some not so responsible people in the media actually fail to remind the readers that the pictures are an artist impression… in other words, how they imagine the planets could look.
The fact is that unfortunately we are not yet able to travel anywhere near other systems. Let’s put the thing in perspective:
- The Moon’s average distance to Earth, the farthest ever any human has traveled, is 384,402 km.
- Mars, most possible the next human destination in space, is around 56 million km when it’s closest to us (though actually that is not such a good indication about the distance a possible trip there would cover)
- The spacecraft that has traveled farthest away from us is Voyager 1. Since 2014 flying in interstellar space, which means it is outside of the Sun’s neighborhood. This is an incredibly amazing feat! It took the ship 37 years to get there. And for those of thinking that it must be a slow one because it is so old now, sorry to disappoint again! It is actually the fastest vehicle ever made. So how far is it? About 20,600 million km from the Earth.
- And how far is Trappist-1? About 40 light years away, which is about 3.8 x 10^14 km (those are 14 zeroes!) or 380 million million km, or 18,000 times the distance to Voyager 1.
So as you can see we are not going to get any nice photographs of these planets anytime soon, much less travel there, regardless of how habitable they might be. So if you were packing your luggage… sorry to disappoint again!
So why should you care?
Because even with all these limitations, we can still listen there! Have you seen Contact? That’s obviously just a movie, but it shows what scientists have been trying to do for some time with SETI and also promoting new projects as recently as 2015.
The difficult decision with those projects is where to listen, where to point the antennas to. A system with 3 possibly habitable planets seems like a great candidate! If we ever find evidence of extraterrestrial intelligent life, we need to find planets like those.
Also, let’s think big and long term. Maybe one day in the far future we will actually be able to send spacecrafts to other stars. Maybe some millennia in the future people will celebrate this discovery. Maybe even they will make another doodle about it.