As curious as it is when we were kids, we always tend to
look up in the sky then wonder if there’s a life other than us? Aliens as we
call them and we’ve only braced our imagination through the movies, still,
questions never answered.
The National Aeronautics and Space Administration or NASA
keeps on looking at every angle in the universe in search for life.
Then year 2015, came a great discovery… They are calling it
The Exoplanets.
NASA's Kepler space telescope celebrated its 1,000th
exoplanet discovery earlier this month, an impressive milestone in the search
for life on other worlds.
Just for a quick glance on what Exoplanet is, according to Wiki, an exoplanet or extrasolar planet is a planet that orbits a
star other than the Sun, a stellar remnant, or a brown dwarf. Nearly 2000
exoplanets have been discovered (1931 planets in 1221 planetary systems
including 484 multiple planetary systems as of 6 July 2015). There are also
rogue planets, which do not orbit any star and which tend to be considered
separately, especially if they are gas giants, in which case they are often
counted, like WISE 0855−0714, as sub-brown dwarfs.
The Kepler space telescope has also detected a few thousand
candidate planets, of which about 11% may be false positives. There is at least
one planet on average per star. Around 1 in 5 Sun-like stars have an
"Earth-sized" planet in the habitable zone, with the nearest expected
to be within 12 light-years distance from Earth. Assuming 200 billion stars in
the Milky Way, that would be 11 billion potentially habitable Earth-sized
planets in the Milky Way, rising to 40 billion if red dwarfs are included. The
rogue planets in the Milky Way possibly number in the trillions.
The nearest known exoplanet, if confirmed, would be Alpha
Centauri Bb, but there is some doubt about its existence. As of March 2014, the
least massive planet known is PSR B1257+12 A, which is about twice the mass of
the Moon. The most massive planet listed on the NASA Exoplanet Archive is DENIS-P
J082303.1-491201 b, about 29 times the mass of Jupiter, although according to
most definitions of a planet, it is too massive to be a planet and may be a
brown dwarf instead. There are planets that are so near to their star that they
take only a few hours to orbit and there are others so far away that they take
thousands of years to orbit. Some are so far out that it is difficult to tell
if they are gravitationally bound to the star. Almost all of the planets
detected so far are within the Milky Way, but there have also been a few
possible detections of extragalactic planets.
The discovery of exoplanets has intensified interest in the
search for extraterrestrial life, particularly for those that orbit in the host
star's habitable zone where it is possible for liquid water (and therefore
life) to exist on the surface. The study of planetary habitability also
considers a wide range of other factors in determining the suitability of a
planet for hosting life.
Any being can’t live without water. It’s essential for life.
Now astronomers are homing in on those exoplanets that may have liquid water,
which is thought to be essential for supporting life. And according to new
research, so-called "super-Earths" may host vast oceans that last for
billions of years.
A super-Earth is an extrasolar planet whose mass is greater
than Earth's but smaller than that of gas giants like Neptune and Uranus.
Earth's mantle holds vast amounts of water, which returns to
the surface through volcanism. Since this "recycling" process is
crucial for maintaining our planet's oceans, researchers from the
Harvard-Smithsonian Center For Astronomy (CfA) wondered if a similar process
might occur on super-Earths.
To find out how long it would take oceans to form on various
super-Earths, the researchers used computer simulations on them, and whether
the oceans could be sustained.
Did they find anything? Super-Earths between two and four
times Earth's mass seem to be even better than Earth at establishing and
maintaining oceans. In fact, the research suggested that the water on these planets
could last for at least 10 billion years. Imagine that!
According to Laura Schaefer, the finding may give
astronomers one more thing to consider when figuring out which exoplanets are
likeliest to harbor extraterrestrial life. Laura Schaefer is a CfA graduate
student and the leader of the research effort.
"When people consider whether a planet is in the
habitable zone, they think about its distance from the star and its
temperature," Schaefer said at a press conference. "However, they
should also think about oceans, and look at super-Earths to find a good sailing
or surfing destination."
The findings were presented in Seattle Jan. 8 at the annual
meeting of the American Astronomical Society.
Yes we have discovered that there’s water on Exoplanets, we
even discovered water on some moons.
The question remains though, is there
really life out there? Or we simply can live there sometime…
Cheerio!
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