- 4278 - MARS - Solar wind effects? - A rare void from the sun briefly blew up Mars' atmosphere last year, 2022, and it could happen to Earth too. On December 26, 2022, the MAVEN Orbiter witnessed Mars' magnetic shield and atmosphere drastically "balloon" outward by thousands of miles. The sudden expansion was triggered by a rare gap in solar wind.
-------------------------- 4278 - MARS - Solar wind effects?
- Mars' atmosphere
briefly blew up to around three times its normal size without warning, leaving
scientists puzzled. Now, researchers have discovered that the expansion was
triggered by a rare gap, or "void," in the charged particles that
continuously stream out of the sun, known as solar wind.
-
- This sudden
atmospheric "ballooning" has also happened on Earth at least once
before and could happen again soon.
-
- “Mars Atmosphere
and Volatile Evolution” (MAVEN) Orbiter has been circling the Red Planet's
upper atmosphere since 2014. This year,
2023, it witnessed Mars' magnetic shield, or magnetosphere, swell outward by
"thousands of miles". This enabled the wispy Martian atmosphere to
temporarily expand and fill the extra space.
-
- The atmospheric
expansion coincided with a 100-fold decline in solar wind particles hitting the
spacecraft.
-
- Normally, solar
wind constantly bombards Mars and every other planet in the solar system, which
has caused Mars to lose most of its atmosphere. Mars' magnetosphere, or what is
left of it, is always pushing against the solar wind, which diverts most of the
streaming particles around the planet.
-
- However, when the
solar wind dropped off there was nothing for the magnetosphere to push against,
so it "ballooned" outward. As
soon as the solar wind returned to normal it shoved the magnetosphere back into
place.
-
- A similar
phenomenon occurred on Earth in 1999, when the solar wind "nearly
vanished" for three days (May 10 to 12), which enabled our atmosphere to
swell up to 100 times its normal volume before eventually returning to its
previous size.
-
- These sudden
disappearances of solar wind are the result of rare gaps in the streaming
particles. These gaps occur because unusually fast particles in solarwind
sometimes catch up to or overtake the particles ahead, leaving a space where
solar wind would normally be.
-
- In a 2008
researchers linked the 1999 atmospheric expansion event on Earth to a large
"coronal hole," or gap in the solar surface, that appeared shortly
before our planet's atmosphere swelled. Coronal holes have weaker magnetic
fields than the rest of the sun, which enables solar wind to race out of the
sun faster than normal.
-
- Coronal holes
could become more common over the next few years as the sun reaches the
explosive peak of its roughly 11-year cycle of activity, known as the solar
maximum.
-
- Data from NASA's
InSight mission shows that Mars's rotation is speeding up and its days are
growing slightly shorter. Like an ice
skater tucking their arms for an elegant spin, the planet Mars appears to be
rotating slightly faster with each passing year.
-
- Data from NASA's
InSight mission shows that the Red Planet's spin is accelerating at a rate of 4
milliarcseconds, one one-thousandth of an arcsecond, a unit of angularity per
year. As a result, the length of a Martian day is getting shorter by fractions
of a millisecond annually.
-
- Such changes in
rotation can be difficult to detect. Luckily, InSight was able to collect over
four years of data before it ran out of power in December 2022. The new study
examined measurements taken from the mission's first 900 days on Mars, enough
time to pick up on even subtle changes in planetary spin.
-
- By bouncing radio
waves into space and assessing how long they took to get back to the surface of
the planet, InSight painted a detailed portrait of the planet's spin.
Scientists aren't 100% sure what's causing the acceleration, but they have a
few ideas. One is that ice accumulation at the planet's poles is causing a
slight change in how its mass was distributed.
-
- Or, the
researchers hypothesize, it could be due to a phenomenon called post-glacial
rebound, where landmasses rise up after millennia buried under the ice. In
either case, the gradual shift might have been enough to subtly change Mars's
rotation over huge spans of time.
-
- In addition to
tracking the planet's spin, InSight's data provided an unprecedented look into
Mars's core. Upon analyzing it, researchers discovered that the Martian core
has a radius of about 1,150 miles, smaller than Earth's 2,165 mile core, but
larger in proportion to the planet.
-
- The study also
revealed that this core is not uniform. Instead, it has regions of higher or
lower density, causing its molten material to "slosh" as Mars spins.
This could be possible reason for the Red Planet's accelerated spin.
-
-
December 15, 2023
MARS -
Solar wind effects?
4273
------------------------------------------------------------------------------------------
-------- Comments
appreciated and Pass it on to whomever is interested. ---
--- Some reviews are
at: -------------- http://jdetrick.blogspot.com -----
-- email feedback,
corrections, request for copies or Index of all reviews
--- to: ------
jamesdetrick@comcast.net
------ “Jim Detrick” -----------
--------------------- ---
Tuesday, December 19, 2023 ---------------------------------
No comments:
Post a Comment