Download NASA has discovered 7 Earth-like planets orbiting a

NASA has discovered 7 Earth-like
planets orbiting a star just 40 lightyears away
This tiny star has 7 planets that
potentially could be suitable for life.
https://www.youtube.com/watch?v=v5Xr-WkW5JM&feature=youtu.be
• The first step in finding life outside our own planet is to find a planet like
our own: small, rocky, and at just the right distance from the star that
liquid water could exist on its surface.
• That’s why an announcement today from NASA is so exciting: The space
agency, along with partners around the world, has found seven potentially
Earth-like planets orbiting a star 40 light-years away.
• “It’s the first time that so many planets of this kind are found around a
same star,” Michaël Gillon, the lead author of the Nature paper
announcing the discovery, said in a press conference. “The seven planets
… could have some liquid water and maybe life on the surface.”
• Three of the planets are directly in the star’s habitable zone, meaning
water can mostly likely exist on the surface of them. One of them, Gillon
said, has a mass “strongly to suggest a water-rich composition.” And it’s
possible that the other four could have liquid water, too, depending on the
composition of their atmospheres, the astronomers said.
http://www.mirror.co.uk/science/exoplanet-discovery-take-360degree-9901232
The planets “e,” “f,” and “g” — marked in
green are directly in the “habitable zone” of
this star system. NASA
• The exoplanets orbit a star in the constellation Aquarius
called Trappist-1. And it’s a solar system very different from
our own.
• For one, Trappist-1 is a tiny, “ultra-cool” dwarf star. It’s cool
because it’s small: just about a tenth of the mass of our sun
and about one-thousandth as bright. But its low mass
allows its planets to orbit it very closely and remain in the
habitable zone.
• The distance at which the planets orbit Trappist-1 is
comparable to the distance of Jupiter to its moons. All the
planets are believed to be rocky, and are all believed to be
around the size of Earth, give or take 10 to 20 percent.
• The star’s dimness is actually what led to the
discoveries of these planets. When
astronomers search for exoplanets, they
typically look for a temporary dimming of a
star — an indication that a planet has passed
in front of it. This method makes it hard to
find small, rocky worlds orbiting big, bright
stars. If the planets are too small, they’ll get
washed out.
Artist conceptions of the seven planets of TRAPPIST-1 with their orbital periods, distances
from their
•
•
•
•
“Maybe the most exciting thing here is that these seven planets are very well
suited for detailed atmospheric study,” Gillon said. The James Webb Space
Telescope, set to launch in 2018, will have the ability to measure the chemical
composition of exoplanet atmospheres. If the atmospheres contain telltale gases
like ozone, oxygen, or methane, life could exist there. “We can expect that in a few
years, we will know a lot more about these [seven] planets,” Amaury Triaud,
another of the paper’s co-authors, said.
If this all sounds a bit familiar, it’s because astronomers announced three
potentially habitable planets around Trappist-1 in May. Today’s reveal adds four
more to the mix.
Right now, the astronomers are beginning to study the planets’ atmospheres with
the telescopes they have. And from these observations, they feel fairly confident
that the worlds are rocky. “For detailed characterization, we will need James
Webb,” Triaud said.
In the meantime, we just have our imaginations to fill in the gap. This is an artist’s
rendition of what the fifth planet in this bizarre solar system might look like. These
planets are believed to be tidally locked to the star, each has a permanent day side
and a permanent night side. And because the planets are so close together, they’d
appear in the sky like moons.
• The more Earth-like exoplanets astronomers find in the galaxy, the more
they update their estimates of how many Earth-like planets could be out
there. “For every transiting planet found, there should be a multitude of
similar planets (20–100 times more) that, seen from Earth, never pass in
front of their host star,” Nature reporter Ignas Snellen explains in a feature
article. And the more exoplanets there are, the more likely it is that life
exists on at least one of them.
• “With this discovery we’ve made a giant, accelerated leap forward in our
search for habitable worlds and life on other worlds potentially,” Sara
Seager, a leading exoplanet expert at MIT, said during the announcement.
This one star system, she said, gives astronomers many chances to look for
life, and refine their understanding of exoplanets in small-star systems.
• Also promising: Tiny, cool stars like Trappist-1 are some of the most
common in the galaxy. Investigating them will likely yield more exoplanet
discoveries. Which will help get us closer to finding places like Earth.
• As NASA associate administrator Thomas Zurbuchen said, “Finding
another Earth-like planet isn't a matter of if but when.“