Download RAW #17-February 14

Article #17
Name:
Grade: _____/15
Your Tasks:




Read the article
Annotate the article--highlight the main point(s) of the article and other
details you found interesting within the article, also making marginal note
to coincide with your highlighting.
Mark at least two(2) words for which you do not know the definition. You
will look up the definitions and write the words and their definitions at the
end of the article in the space provided.
Write a MINIMUM of four (4) full sentences reflecting on the article. Did
you have any questions about the article? Did you find anything
interesting? Did it make you think of something else/similar? Did anything
strike you are strange, wrong, funny, etc.?
Scientists study exoplanet's atmosphere for signs of life
By Scientific American, adapted by Newsela staff
01.26.17
Astronomers have been looking around other stars for planets that resemble the earth.
So far, they have not found an exact sibling. But, they may have found a cousin.
This cousin is called GJ 1132 b. It is an exoplanet, which is a planet outside our solar
system. Thousands of exoplanets have been discovered in different sizes. They have
different orbits, but all orbit stars other than the sun.
GJ 1132 b weighs about one Earth mass, but it circles its star in a warm orbit. This
means it could be more like Venus than Earth. The diameter of GJ 1132 b is nearly 50
percent larger than that of Earth. This suggests it has a thick atmosphere. A European
team of scientists has found hints that the exoplanet might contain water and gas.
Search For Habitable Planets Starts Here
Discoveries of exoplanets are becoming more common. And so are efforts to learn
more about their compositions, climates and histories. Astronomers detected the first
exoplanet atmosphere more than 15 years ago. But, they have only managed to
observe a handful ever since. Most have been very hot planets as big as Jupiter or even
larger. GJ 1132 b allows astronomers to examine the atmospheres of smaller, more
Earth-like worlds.
“We have shown that an Earth-mass planet is capable of sustaining a thick
atmosphere,” says John Southworth of Keele University in England. He's the lead
author on a paper about the discovery of GJ 1132 b. “This is one step towards
investigating whether a planet could host life.”
It is difficult to study atmospheres around other worlds because of technology
limitations. Luckily, GJ 1132 b is relatively easy to study because it is only 39 light-years
away. A light-year is how scientists measure distance in space. One light-year is about
6 trillion miles. That's the distance a beam of light travels in one year. GJ 1132 b also
orbits a type of star called M-dwarf, which is the smallest and coolest type of star. This
allows astronomers to more easily study the planet’s atmosphere.
“Detecting the atmosphere of Earth-sized planets around M-dwarfs is an essential step
in the search for habitable exoplanets,” says astronomer Julien de Wit. He is a
researcher at Massachusetts Institute of Technology and wasn't involved in the study.
“Finding one with an atmosphere would provide us with hope.”
Getting A Closer Look
The team studied GJ 1132 b’s atmosphere by observing when it crosses over the face
of its star as seen from Earth. As the planet crosses its star, it blocks a small portion of
the star’s total light. This means it casts a shadow toward our solar system. A planet’s
atmosphere will absorb a tiny fraction of starlight around the shadow’s edges. This
requires observing its crossing using the world’s most powerful telescopes.
The team was able to do so for GJ 1132 b using a telescope at the European Southern
Observatory in Chile. Their results showed water and methane in GJ 1132 b’s
atmosphere are possible. They were in nearly equal proportions as they are here on
Earth.
Astronomers have good measures for both the mass and the size of GJ 1132 b. This
means they can estimate the planet’s thickness, and also its possible composition. It is
possible the planet could be steamy with a lot of water surrounding a rocky core. But,
rockier compositions are also possible. Astronomers still don't know the exact interior
makeup of GJ 1132 b, Southworth says. “The next step is to take observations with
bigger telescopes and space telescopes," he added.
"Planet Hunters Will Have To Wait"
Current instruments are limited. But the next generation of telescopes, such as the
James Webb Space Telescope (JWST), will offer more information about the nature of
Earth-size exoplanet atmospheres.
Renyu Hu, a planetary scientist at the NASA Jet Propulsion Laboratory, says that the
JWST will allow scientists to observe exoplanets like GJ 1132 b in greater detail.
"Perhaps GJ 1132 b will be one of the more interesting exoplanets to be observed
extensively,” Hu said.
JWST has a mirror about six times the size of the Hubble Space Telescope’s. This
allows it to efficiently seek out signs of carbon dioxide and oxygen, as well as water
vapor and methane in some exoplanet atmospheres.
However, eager planet hunters will have to wait a little while longer because the JWST
will not launch until October 2018. And, it already has a full schedule of other science
objectives. This will likely limit any time-consuming observations of exoplanets, such as
GJ 1132 b.
“This is a great start,” said Sara Seager, a professor of astrophysics at MIT. “We need
to await the JWST to make any real progress on small-planet atmospheres,” she said.