- 4525 - PLANETS - that may support life? - The search for habitability elsewhere in the universe can be reduced to the search for water. We haven't yet found lifeforms that detach this substance from our conception of "life" itself, so we have no choice but to accept the cosmic water trail as our north star in the quest to find worlds that mirror our own.
--------------------------------------- 4525 - PLANETS - that may support life?
- Scientists jump for joy a little when they
find an exoplanet likely to hold any water, but particularly liquid water,
rather than ice or water vapor. There
is a tantalizing planet outside the solar system may have a temperate water
ocean about half the size of the Atlantic.
-
- Of all currently known temperate
exoplanets, “LHS 1140 b” could well be our best bet to one day indirectly
confirm liquid water on the surface of an alien world beyond our solar system.
-
- “LHS 1140 b” exoplanet orbits a red dwarf star about a
fifth the size of the sun and sits 48 light-years away from Earth in the
constellation “Cetus” which translates to "the whale."
-
- But most important about LHS 1140 b is the
fact that it lives in its star's habitable zone, otherwise known as its
"Goldilocks zone." This is
the area around a star where it's neither too hot nor too cold for a world to
host liquid water, but rather fits the standard by which the fairy tale
character Goldilocks lives.
-
- This is the first time we have ever seen a
hint of an atmosphere on a habitable zone rocky or ice-rich exoplanet. The analysis of LHS 1140 b's atmosphere
might have even found evidence of "air" on it. The exoplanet could be either rocky or icy.
-
- “LHS 1140 b” lore has been making headlines
now due to the new study involving JWST data, LHS 1140 b has actually been on
planetary hunters' radars for some time. In fact, experts had already theorized
that this could be a water world in the past, and even shared similar
sentiments about how it could offer humanity the first-ever direct evidence of
exoplanetary liquid water.
-
- None of that is new. An army of telescopes has investigated it in
solid detail, including the now-retired Spitzer telescope, the Hubble Space
Telescope and the Transiting Exoplanet Survey Satellite (TESS). However, there was something missing until
now: the James Webb Space Telescope's.
-
- It was necessary because, for a long time,
there was something like a gap in the literature about LHS 1140 b. Basically,
the trouble was that scientists couldn't quite confirm whether the exoplanet is
a mini-Neptune, a planet less massive than our original Neptune, but one that
still has Neptunian characteristics, or a super Earth.
-
- A “super Earth” is a world that's larger
than Earth, but still either rocky or water-rich. This work not only "strongly
excluded" the mini-Neptune scenario, but also confirmed the world may have
a nitrogen-laced atmosphere like Earth does.
While it is still only a tentative result, the presence of a
nitrogen-rich atmosphere would suggest the planet has retained a substantial
atmosphere, creating conditions that might support liquid water.
-
. “LHS 1140 b” isn't exactly fully alone in
its exhilarating characteristics; there are also a variety of other
habitable-zone exoplanets scientists are drawn to. The most obvious are
probably the seven worlds of the TRAPPIST-1 system, a planetary lineup that
looks almost disturbingly similar to our solar system's structure. The septet
of orbs resembles our octet (bye, Pluto) and some of them are in the habitable
zone like Earth is.
-
- JWST study actually complicated the search
for habitability in TRAPPIST-1 quite recently. It revealed that the system's
anchor star is incredibly active in such a way that it could skew our
observations, making us believe a world in the system is habitable when it
really isn't. Even the JWST has its limitations.
-
- JWST data suggests the exoplanet's mass
might be made of between 10 percent and 20 percent liquid water, and, it paints
a fantastical picture of what the planet might look like in simple terms. It
could look like a snowball, essentially, that orbits its star while rotating in
such a way that one side always faces that star.
-
- It's kind of like the moon's orbit around
Earth; we can't ever see the far side of the moon because the moon rotates at
the same rate it revolves around Earth. One side never faces us, and the other
always does.
-
- Similarly, this would mean that, if the
JWST's illustration of the LHS 1140 b scene is correct, the side of the planet
always facing its sun would be exposed to lots of heat. This would be the part
of the snowball that's "melted" into a liquid ocean.
-
- Current models indicate that if LHS 1140 b
has an Earth-like atmosphere, it would be a snowball planet with a bull's-eye
ocean about 2,485 miles in diameter. The
surface temperature of the ocean may very well even be a "comfortable" 68 degrees Fahrenheit.
-
- Far more work must be done, especially with
the JWST, in observing the nuances of LHS 1140 b which is always nice to have a
lead to follow when searching for needles in a vast haystack. This is a very promising start.
-
-
July 10, 2024 PLANETS - that
may support life? 4525
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