- 4405 - PLANETS - how do atmospheres vary? - What can they teach us about finding life beyond Earth? Why study impact craters, planetary surfaces, exoplanets, astrobiology, solar physics, and comets, and what these fantastic scientific fields can teach researchers and space fans regarding the search for life beyond Earth?
------------------------- 4405 - PLANETS - how do atmospheres vary?
- Planetary atmospheres play a key role in
better understanding our own solar system. It can teach us about finding life
beyond Earth. We think the sun was much
dimmer in the early history of the solar system, yet Earth and Mars each were
as warm or warmer than now. How is this possible?
-
- Venus and Mars have carbon dioxide
dominated atmospheres with more CO2 in the vertical column than Earth. Yet one
is colder than Earth and the other warmer. Even though Venus is closer to the
sun its clouds reflect so much light that it effectively has less sunlight than
Earth, yet its surface is warm enough to melt lead. How is this possible?
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- We need to understand other atmospheres to
understand the past and future of Earth.
Aside from Earth, Venus, and Mars, the other planetary bodies in our
solar system that possess atmospheres include Jupiter, Saturn, Uranus, Neptune,
dwarf planet Pluto, and Saturn’s largest moon, Titan, which is the only solar
system moon with a dense atmosphere.
-
- The formation and evolution of these
atmospheres are what scientists are attempting to better understand via
computer models that are often combined with data obtained by ground- or
space-based telescopes. Through this, scientists have learned, and continue to
learn, a great deal about the atmospheres of these intriguing and mysterious
worlds that inhabit our solar system. But even with all the instruments and
technological advancements, what are some of the benefits and challenges of
studying planetary atmospheres?
-
- The same climate models used for Earth are
now used for other planets, such as Mars. When the models fail on Earth it is
tempting to force them to match Earth data rather than fixing the physics and
chemistry in the models. Having the examples from other planets force us to
look for errors in Earth models or in our understanding of how Earth climate
models work.
-
- Planetary atmospheres within our own solar
system range from sulfuric acid and carbon dioxide (Venus) to carbon dioxide
(Mars) to hydrogen and helium (Jupiter, Saturn, Uranus, and Neptune) to
nitrogen and methane (Titan and Pluto).
-
- Despite the sulfuric acid within Venus’
atmosphere, past studies have postulated the possibility of Venus’ higher
altitudes potentially having the ingredients to support life as we know it.
These unique worlds could offer a glimpse of what scientists could find beyond
our solar system, known as exoplanets.
-
- What can studying planetary atmospheres
within our own solar system teach us about exoplanet atmospheres? We expect a wide range of exoplanetary
atmospheres, some are so hot that they likely are raining metals. Even in the
solar system there are planets raining condensed natural gas. So, the solar
system planets are analogs for exoplanets, but there are definitely exoplanets
very different from solar system planets.
-
- Since the distance to exoplanets ranges
from a few light-years to hundreds of light-years, it takes extremely powerful
instruments to study their atmospheres. James Webb Space Telescope (JWST) has
examined the atmospheres of several exoplanets, including “WASP-39 b”, which is
located just under 700 light-years from Earth.
-
- With its powerful infrared instruments,
JWST successfully identified water, carbon dioxide, and potassium on this
Jupiter-sized world. As demonstrated on Earth, water is essential for life as
we know it. Therefore, finding water on an exoplanet could indicate its
likelihood for life, as well.
-
- Out of the almost 5,600 confirmed
exoplanets to date only 69 are deemed potentially habitable. This is primarily
due to their orbit residing within their star’s habitable zone (HZ), meaning
they orbit at the correct distance from their star for liquid water to
potentially exist on its surface, assuming the exoplanet is terrestrial (rocky)
like Earth. But finding water within an exoplanet’s atmosphere could also pose
the prospect for finding life, as well.
-
- What can studying planetary atmospheres
teach us about finding life beyond Earth?
The Earth’s atmosphere is out of chemical balance due to emissions of
various gases by life. The oxygen in
Earth’s atmosphere is not compatible with the methane in the atmosphere. The
methane is largely a waste product of life. So, trying to detect life elsewhere
is most likely going to start with looking at the chemistry of exoplanet
atmospheres for signs of chemical imbalance.
-
- The scientific discipline responsible for
studying planetary atmospheres is known as atmospheric science and encompasses
several sub-disciplines, including computer science, astronomy, physics, and
meteorology, just to name a few. It is through constant collaboration and
innovation of these sub-disciplines that allows scientists to study planetary
atmospheres both within and beyond our solar system.
-
- The most interesting is Mars, because there
is a lot of data for Mars, and Mars once had a climate more like Earth’s than
the barren desert it is now. Titan, a moon of Saturn is also interesting
because it has methane rain, and lakes and seas of hydrocarbons. It also is
shrouded in a haze composed of complex organic material.
-
- How will planetary atmospheres help us
better understand our place in the universe in the coming years and decades?
Only time will tell, and this is why we science!
-
-
March 25, 2023 PLANETS
- how do atmospheres vary? 4405
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------ “Jim Detrick” -----------
--------------------- --- Wednesday, March 27,
2024
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