- Astronomers are vigilantly scanning the skies
for asteroids that veer
into Earth's solar system neighborhood,
but some are hidden.
Most asteroids, left over rubble
from our solar system's formation
about 4.6 million years ago, orbit the sun
between Mars and Jupiter.
Millions exist out there, but in the inner solar system,
asteroids are obscured by the blinding glare of the sun.
Now, a new survey of space rocks
in regions around the orbits of Venus and Mercury
have spotted sizable asteroids
in this elusive zone of space.
One is nearly a mile wide, the type of planet killer rock
that would decimate life on earth.
Fortunately, these rocks
don't currently pose any danger to our planet,
nor will they for the foreseeable future.
Though over centuries, or much longer,
one of the asteroids' orbits may change
and potentially pose a threat.
To find these rocks,
scientists must scour the sky at twilight.
They get just 10 minutes.
At dusk, for example, they have the narrow viewing time
after the sun is dimmed,
but before the sun facing sky disappears under the horizon.
"You don't have a lot of time, "
aid Scott Sheppard, an astronomer
sat the Carnegie Institution for Science.
Sheppard led the new research
about these twilight asteroid discoveries,
which was recently published in the Astronomical Journal.
A powerful telescope is needed to find these rocks.
At 7,200 feet up in Chile,
scientists attached a camera called the dark energy camera
to a 4-meter wide telescope.
It's about 13 feet.
"It's the biggest camera on a telescope
of such a large size,"
explains Sheppard.
And it can view great swaths of the sky.
Previously astronomers used it to look
for truly deep space objects beyond Pluto.
In just one image, scientists can view a region of sky
encompassing about 11 full moons,
as opposed to their previous twilight viewing capabilities
of around two full moons.
So far, they've spotted 3 "near-Earth asteroids" or NEAs.
It doesn't actually mean they're literally near Earth,
like the moon.
It means they're relatively near - because space is huge.
These are rocks whose orbit can at times pass
within some 30 million miles of Earth's orbit
around the sun, not necessarily Earth itself.
The designation also doesn't mean they're a threat.
No known asteroid over 460 feet across
will threaten Earth in the next century or so.
"Crucially, the chances of a major impact in our lifetime
is, as far as we know, extremely small,"
said Eric Christensen,
the Director of the near-asteroid seeking
Catalina Sky Survey in Arizona.
As Mashable reported, impacts by objects around 460 feet
in diameter occur every 10,000 to 20,000 years.
And a dinosaur killing impact from a rock
perhaps half a mile across or larger
happens on 100-million-year time scales.
Though something smaller could certainly surprise us
like the unexpected football field sized asteroid
that swung just 40,000 miles from Earth in 2019.
That's why watching is critical.
We might not be able to nudge
an approaching rock away from our planet.
That's an ambitious space endeavor that takes years
of planning, but we can prepare
for an impact and move people out of the way.
Two of the three newly revealed asteroids, however,
are indeed of "planet-killer" size.
They likely came from the main asteroid belt
where most asteroids live.
"The near Earth asteroids are on eccentric orbits
that are stable for a million years or so,"
explained Sheppard.
But as they interact with the gravity of nearby planets,
their orbits can shift.
Eventually, they'll most likely be ejected
to the outer solar system.
The largest of these objects, 2022 AP7,
is expected to pass extremely close to Venus,
like within a few thousand miles in the next 1000 years.
It could potentially hit Venus,
but that that probability remains low.
That's why this colossal rock also earns the designation
of, "Potentially Hazardous Asteroid,"
meaning it's bigger than 460 feet wide
and its orbit passes within 4.6 million miles
of Earth's orbit around the sun.
But that day, if it ever occurs, isn't anytime soon.
That possibility is on the order of centuries
or millennia away.
"There's no danger.
There are no interactions with Earth
in the foreseeable future."
Unfortunately, this reality won't stop some news sites
from publishing misleading and scaremongering headlines
about the newly found space rocks,
such as and I kid you not,
"Huge planet killer asteroid discovered -
and it's heading our way."
That's rubbish.
In fact, anytime a news site or entity on social media
warns of an asteroid "headed our way," ignore it.
These egregious efforts are just seeking your clicks.
These dubious stories are published weekly,
yet NASA has literally never even issued a warning
about a menacing incoming asteroid.
If a space rock ever does become a threat, NASA,
the White House and political leaders will be involved.
To protect humanity from asteroid strikes,
astronomers and planetary defense experts
want to know where most of the near-Earth asteroids
are headed.
If one is projected to one day, perhaps in decades
or centuries, come unsettlingly close to Earth
then we can do something about it.
"You need to know what's coming, when it's coming
and how hard it's going to hit,"
Christensen told Mashable.
Even a smaller asteroid, some 100 to 170 feet across,
could destroy a place like Kansas City,
home to half a million people.
So the surveys for rocks larger and "small" are vital.
With enough time, like years, NASA has recently proven
that we have the ability to slightly change
an asteroid's trajectory and thereby save Earth
from a potential disaster.
The space agency recently crashed a vending machine
size spacecraft in an asteroid the size of a stadium.
The sci-fi like endeavor called DART,
or Double Asteroid Redirection Test,
was a successful mission to see how civilization
could alter the path of a menacing asteroid
should one be on a collision course with our planet.
Of the largest class of near earth space rocks,
those one kilometer wide or larger,
astronomers estimate they've found around 95% of them.
They are non-threatening.
As of November 2022, they've located 857.
That means there are some 20 to 50
of those "planet-killer" asteroids still out there.
Astronomers would like to find more just to be safe.
That means peering into the twilight sky.
As Sheppard said, we haven't found them all.