- 4437 - METEORITES - teach us about our solar system? - Meteorites provide our best information about how the solar system formed and evolved. This includes planet formation. We also obtain information on astrophysics (stellar processes) through studies of pre-solar grains.
------------------------- 4437 - METEORITES - teach us about our solar system?
- Meteorites can teach us about finding life
beyond Earth? Many scientific
disciplines can assist us in better understanding our place in the cosmos and
searching for life beyond Earth. The
research field of meteorites can help us better understand the history of both
our solar system and the cosmos, including the benefits and challenges, finding
life beyond Earth, and potential routes for upcoming students who wish to
pursue studying meteorites.
-
- There is often confusion regarding the
differences between an asteroid, meteor, and meteorite, so it’s important to
explain their respective differences to help better understand why scientists
study meteorites and how they study them.
-
- An asteroid is a physical, orbiting
planetary body that is primarily comprised of rock, but can sometimes be
comprised of additional water ice, with most asteroids orbiting in the Main
Asteroid Belt between Mars and Jupiter and the remaining orbiting as Trojan
Asteroids in the orbit of Jupiter or in the Kuiper Belt with Pluto.
-
- A meteor is the visual phenomena that an
asteroid produces as it burns up in a planet’s atmosphere, often seen as
varying colors from the minerals within the asteroid when heated up. -
- The pieces of the asteroid that survive
the fiery entry and hit the ground are called meteorites. Scientists’ study them to learn about the
larger asteroid body it came from, and where that asteroid could have come
from, as well.
-
- The benefits are scientific knowledge,
information on potential resources , metals, water, for humans to utilize,
information on how to link meteorites and asteroids, which can provide
information on space collision hazards for Earth.
-
- The challenge ,compared to Earth rocks, are
we lack field evidence for their source bodies and parent bodies we have to
factor in the element of time that is longer for space rocks than for Earth
rocks, and sometimes we are dealing with formation environments completely
unlikely what we have on Earth.
-
- More than 50,000 meteorites have been
retrieved from all over the world, ranging from the deserts of Africa to the
snowy plains of Antarctica. In terms of their origins, it is estimated that
99.8 percent of these meteorites have come from asteroids, with 0.1 percent
coming from the Moon and 0.1 percent coming from Mars.
-
- The reason why we’ve found meteorites from
the Moon and Mars is due to pieces of these planetary bodies being catapulted
off their surfaces after experiencing large impacts of their own, and these
pieces then travel through the Solar System for thousands, if not millions, of
years before being caught in Earth’s gravity and the rest is history. Therefore, with meteorites originating from
multiple locations throughout the Solar System, what can meteorites teach us
about finding life beyond Earth?
-
- The ingredients for making life formed in
space and were delivered to Earth. We
know organic molecules formed in gas clouds, were incorporated in our solar
system, and processed in asteroidal and cometary bodies under higher
temperatures in the presence of water.
-
- These were then delivered to Earth which
wouldn’t have been very hospitable in early times due to sterilizing impacts.
We also know that there must have been a lot of planetary rock swapping early
when impact rates were high. Life itself may have been transplanted to Earth
from Mars.
-
- As it turns out, one of the most
fascinating meteorites ever recovered did come from Mars, which was identified
as “ALH84001”, as it was found in Allan Hills of Antarctica on December 27,
1984, during the 1984-85 field season where researchers from all over the world
gather in Antarctica to search for meteorites using snowmobiles. Despite being
collected in 1984, it wasn’t until 1996 that a team of scientists discovered
what initially appeared to be evidence of microscopic bacteria fossils within
the 4.25-pound meteorite.
-
- ALH84001, which is one of the most famous
meteorites ever recovered, helped catapult the field of astrobiology to new
heights when scientists uncovered what initially appeared to be microscopic
bacteria fossils within this meteorite, though those findings remain
inconclusive to this day.
-
- This immediately made headlines across the
globe, resulting in countless non-scientific claims that these microfossils
were clear evidence of life on Mars. However, both the researchers of the
initial study and the scientific community were quick to point out the
unlikelihood that these features resulted from life based on other observations
made about ALH84001.
-
- For example, while ALH84001 is estimated to
be 4.5 billion years old, which is when Mars is hypothesized to have possessed
liquid water on its surface, radiometric dating techniques revealed that
ALH84001 was catapulted off Mars approximately 17 million years ago and landed
on Earth approximately 13,000 years ago.
-
- To this day, there has been no clear
evidence that ALH84001 ever contained traces of life. Despite this, ALH84001
has nonetheless helped launch the field of astrobiology into new heights, with
present-day scientists claiming this one meteorite was the reason they pursued
their career path to find life beyond Earth.
-
- Radiometric dating is used to estimate the
ages of meteorites by measuring the radioactive isotopes within the sample. It
is through this constant collaboration and innovation that scientists continue
to unlock the secrets of meteorites with the goal of understanding their
origins and compositions, along with how our Solar System, and life on Earth
(and possibly elsewhere), came to be.
-
- While meteorites are space rocks that crash
land on Earth after traveling through the heavens for millions, and possibly
billions, of years, these incredible geologic specimens are slowly helping
scientists’ piece together the origins of the Solar System and beyond, and even
how life might have come to be on our small, blue world, and possibly
elsewhere.
-
- With a myriad of tools and instruments at
their disposal, scientists from all over the world will continue to study
meteorites in hopes of answering the universe’s toughest questions. Rocks from space are the best kinds of rocks
to study. Way more cool than most rocks on Earth because they are in some ways
more puzzling. How will meteorites help
us better understand our place in the cosmos in the coming years and decades?
-
-
April 17, 2023 METEORITES
- teach us about our solar
system? 4437
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--------------------- --- Thursday, April 18,
2024
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