Scientists think it may have come from another solar system
By Ben Turner for Livc Science
January 30, 2023
–- Scientists have spotted an enormous, 'alien' comet streaking straight
towards the sun.
The 3.7 mile-wide (6
kilometers) space iceball, called 96P/Machholz 1, is thought to have come from
somewhere outside our solar system, and is being monitored by the European
Space Agency’s (ESA) Solar and Heliospheric Observatory (SOHO) spacecraft as it
zips toward our star inside the orbit of Mercury, leaving an icy trail in
its wake.
Comet tails are
primarily composed of gas, which trickles behind the frozen clumps of ice and
gas as they are heated by the sun’s radiation. In 2008, an analysis of the
material shed by 150 comets found that 96P/Machholz 1 contained less than 1.5%
of the expected levels of the chemical cyanogen, while also being low in carbon —
leading astronomers to conclude that it could be an interloper from another
solar system. Now, its plunge towards the sun might reveal even more
of its secrets.
"96P is a very
atypical comet, both in composition and in behavior, so we never know exactly
what we might see," Karl Battams, an astrophysicist at the Naval
Research Lab in Washington DC, told spaceweather.com. "Hopefully we
can get some beautiful science out of this and share [it] with everyone as soon
as we can."
David Machholz first
spotted the eponymous comet in 1986 using a homemade cardboard telescope. Most
comets that fall towards the sun tend to be smaller than 32 feet (10 meters)
wide, and consequently get burned up as they approach our star.
But the gigantic size
of Machholz 1 (it is more than two-thirds the height of Mount Everest) appears
to protect it from complete evaporation, and the SOHO has spotted the comet
making five close passes around the sun since its discovery. The icy
interloper's closest approach to the sun will come on Tuesday (Jan 31.) when it
will near our star at a distance three times closer than Mercury.
The comet may have
found itself on its strange orbit after being ejected from its original solar
system by the gravity of a giant planet. Then, after a considerable
amount of time wandering the cosmos, an accidental rendezvous with Jupiter could
have bent its trajectory to ensnare it around our sun. Other theories also
suggest that the comet might not be alien, but may have formed in
poorly-understood regions of the solar system or had its cyanogen blasted off
by repeat journeys around the sun.
SOHO has spotted more
than 3,000 comets since its December 1995 launch, although the spacecraft’s
primary mission is to observe the sun for violent eruptions called coronal
mass ejections, or solar flares that can cause geomagnetic storms on Earth. The
most powerful of these storms can disrupt our planet's magnetic field enough to
send satellites tumbling to Earth, and scientists have warned that extreme
geomagnetic storms could even cripple the internet.
Gigantic
'alien' comet spotted heading straight for the sun | Live Science
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