A huge comet, or megacomet, twice the width of Rhode Island is heading our way.
Don't worry though.
We're safe.
NASA has again used the Hubble telescope to study the enormous comet known as Comet Bernardinelli-Bernstein.
The comet is about 80 miles across and is hurtling toward us from the edge of the solar
system at 22,000 miles per hour.
But the good news is that it won't get closer than about a billion miles from the Sun.
That's slightly farther out than Saturn.
What's interesting about this new study is that NASA has found out that the comet has
the largest nucleus ever seen.
It's about 50 times larger than what we usually find in the hearts of comets.
The whole comet weighs about 500 trillion tons.
That's also about a hundred thousand times greater than the mass of most comets found
near the Sun.
Even though the comet will not harm Earth, if something like this did hit our planet,
it would certainly wreak havoc.
Anything the size of a mile would have global implications.
The asteroid that killed the dinosaurs and caused the Chicxulub crater in the Gulf of
Mexico was about 12km wide.
Bernardinelli-Bernstein is 80 miles across.
So, yeah.
Please, do the math for me.
Something this big could even impact the whole Earth's rotation, and it would completely
mess up the biosphere, let alone the fact that it would mean "hasta la vista" for humanity.
Some people have their own concerns, and they often ask me if there's any chance that a
planet like Saturn could change Bernardinelli's course and make it hit Earth.
Well, not really.
The Sun is the king of the solar system.
The motion of comets is determined by the gravity of the Sun but also by the gravity
of other planets, and a little bit by the gases that get propelled into space as comets
heat up.
Today's scientists have a very good understanding of gravitational forces, so rest assured because
scientists around the globe can make quite accurate predictions of when and where the
comet will be.
Bernardinelli is a trans-Neptunian comet and is coming our way from the Oort cloud.
It will reach its perihelion, the closest point to the Sun, of 10.9 AU in January 2031.
The object won't be visible to the naked eye, but you should be able to observe it with
a decent backyard telescope.
That's 2 years after the Apophis asteroid pays us a visit.
Unlike Bernardinelli, Apophis will pass extremely close to us.
Less than 20,000 miles from our planet's surface.
That's closer than geosynchronous communication satellites.
But NASA has ruled out a collision with Apophis as well.
So, don't worry.
But back to the megacomet.
It was first observed in 2010, when it was about 3 billion miles from the Sun, about
the average distance to Neptune.
Since then, scientists have been carefully studying it with ground and space-based telescopes.
One of the hardest parts of measuring this comet was differentiating its solid nucleus
from the huge dusty coma that surrounds it.
NASA explained on their website that the team had to make a computer model of the surrounding
coma and adjust it to fit the Hubble images.
Then, the glow of the coma was subtracted to leave behind the starlike nucleus.
Scientists compared their data with earlier observations made by the Atacama Large Millimeter/submillimeter
Array (ALMA) in Chile and found that these earlier size estimates aligned with the new
Hubble findings.
However, ALMA's observations showed that the surface of the comet is darker than originally
thought.
By studying the comet, we can learn more about the Oort Cloud, the spherical shell of icy
objects that surrounds our whole solar system.
The Oort cloud is about 5,000 times further away from our Sun than Earth, and that's why
it is so hard to study it.
But comets like Bernardinelli-Bernstein should give us some decent info once they are closer
to us.