- 4449
- COMET DISCOVERIES
? The spacecraft 'SOHO'
discovers its 5,000th comet. In December
1995, an observatory traveled nearly a million miles from Earth as part of a $1
billion mission to study the sun.
------------------------- 4449 - COMET DISCOVERIES ?
- What scientists thought would be a two-year
endeavor for the “Solar and Heliospheric Observatory”, SOHO, turned out to
tremendously exceed expectations. Not only has SOHO become the longest-lived
satellite watching our star, but it has also become a serendipitous yet
prolific comet hunter. And on March 25,2024,
over 28 years since its launch, the observatory discovered its 5,000
comet.
-
- SOHO's instruments are designed to block
the blinding glare of our sun in order to study its extremely faint outer
atmosphere, the corona, which is a billion times fainter than the sun's body
itself. The same technique helps the observatory spot comets as well, including
ones that slingshot around the sun, passing so close to its sizzling surface
that scientists call them "sungrazer" comets. Prior to SOHO's launch,
there were only a couple dozen sungrazers on record.
-
- SOHO has so far discovered more than half
of all known comets, including some sungrazers.
For the past 20 years, volunteers from around the world have pored over
images from the observatory and discovered thousands of these sungrazing
comets.
-
- The newfound, 5,000th comet is a tiny, icy
rock belonging to the Marsden group of comets, one of three major kinds known
to skim past the sun. Scientists think comets of this group are
first-generation descendants of the comet 96P/Machholz, a 3.7-mile-wide rock
that circles the sun once every 5.3 years, most recently in January, 2023. Of
the 5,000 comets spotted by SOHO, only 75 belong to the Marsden group.
-
- Previous SOHO images had detected cometary
shards and a vast dust trail extending ahead and behind 96P, suggesting its
fragmentation also released other comets like the one just discovered. The
milestone 5,000th comet was found by citizen scientist, he was 13 years old.
-
- The dataset of 5,000 comets is not just a
numerical milestone and a testament to citizen science, but also a unique
dataset scientists can continue to mine to find trends in cometary orbits and
other properties of the objects.
-
- The sun's magnetic field is known to shape
and push the comets' stunning tails, so studying sungrazing comets can help
scientists trace our star’s invisible magnetic field and observe its influence.
-
- It's really valuable science.
-
-
April 29, 2023 COMET DISCOVERIES
? 4449
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--------------------- --- Monday, April 29, 2024
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