- 4511
- ASTEROIDS -
close to Earth? This asteroid
will get closer to Earth than any in human history. On Friday, April 13, 2029 a massive asteroid
passes safely past Earth. Asteroid
“Apophis” is 1,230 feet across, larger
than 90% of space rocks.
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------------------------------- 4511 -
ASTEROIDS - close to Earth?
-
- Asteroid “Apophis” will pass just 19,635
miles from Earth’s surface, the closest approach of an asteroid of this size
that humankind has ever experienced. It will pass between Earth’s geostationary
satellites and the Atlantic Ocean, just a tenth of the distance between Earth
and the moon.
-
- “Apophis” will be visible to the naked eye.
As it crosses the Atlantic, a few billion people in Europe, Africa and Asia can
see it for a few hours in the night sky if skies are clear.
-
- “Asteroid 99942”, “Apophis” was discovered on June 19, 2004, by
astronomers at Kitt Peak National Observatory, who revealed that this stony,
S-type asteroid orbits the sun every 324 days and comes close to Earth every
decade or so. It is calculated that it could strike Earth in 2029, 2036 or
2068. It was, therefore, named after Apophis, the Egyptian demon of chaos and
destruction.
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- Even though there was only a 2.7% chance of
a direct hit by Apophis, the devastation caused by it striking Earth led
astronomers to try to understand its orbit in more detail.
An asteroid’s orbit can only be calculated so
far into the future. Although the following time it comes close to Earth, in
2044, it will be at a greater distance, astronomers can only rule out an impact
for the next 100 years.
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- The calculations are difficult because a
close flyby, such as the one in 2029, will alter Apophis’ orbit so that it
could strike Earth in a future orbit. However, astronomers have reduced the
uncertainty in Apophis’ orbit from hundreds to just a few miles.
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- The close pass in 2029 of Apophis is a rare
opportunity to visit, so NASA already has a spacecraft in hot pursuit. This
close pass is seen as the perfect opportunity to learn more about planetary
defense and how an asteroid reacts to passing so close to a body with such
enormous gravity. It’s thought that Apophis will be squeezed so much that
asteroid quakes and landslides could result.
-
- Watching closely will be NASA’s
OSIRIS-Apophis Explorer (OSIRIS-APEX) spacecraft. It’s the identical spacecraft
that 2020 visited Asteroid Bennu. Then called OSIRIS-REx, NASA’s first asteroid
sample-return mission, it returned a package of samples to Utah in September
2023 before re-directing towards Apophis in a mission extension costing NASA
$200 million. OSIRIS-APEX will orbit Apophis for 18 months as it passes Earth
in 2029.
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- The European Space Agency is also
considering a mission to Apophis, the Rapid Apophis Mission for SEcurity and
Safety (RAMSES) mission, to launch in 2027.
What scientists learn from sending spacecraft to study Apophis in 2029
will be about how a relic of the early solar system reacts to gravity. The
findings could be crucial for future Earthlings in hundreds of years when the
massive asteroid poses a bigger threat.
-
- The key to protecting Earth from being hit
by asteroids is knowing where all these are. More than 27,000 asteroids in our
solar system had been overlooked in existing telescope images. But,
thanks to a new AI-powered algorithm, we now have a catalog of them. The
scientists behind the discovery say the tool makes it easier to find and track
millions of asteroids, including potentially dangerous ones that might strike
Earth someday.
-
- It is for those threatening space rocks
that the world would need years of advance warning before trying to deflect
them away from our planet. Most of the
newfound asteroids hover in the asteroid belt between Mars and Jupiter, where
scientists have already cataloged over 1.3 million such rocky shards over the
past 200 years.
-
- The latest bounty includes about 150 space
rocks whose paths glide them within Earth's orbit; however, none of these "near-Earth
asteroids" seem to be on a collision path with our planet. Others are
“Trojans” that follow Jupiter in its orbit around the sun.
-
- Astronomers conventionally find new
asteroids by studying pockets of our sky over and over again, through telescope
images gathered multiple times each night, usually every few hours. While
planets, stars and galaxies in the background remain unchanged from one image
to the next, asteroids are spotted as specks of light that move noticeably,
which are then flagged and verified. From there, orbits of these asteroids are
determined and monitored.
-
- This is really a job for AI. In fact, AI tools designed for asteroid
searches are already approaching levels attainable by humans. The algorithm is known as “Tracklet-less
Heliocentric Orbit Recovery”, or THOR, analyzed over 400,000 archival images of
the sky maintained by the National Optical-Infrared Astronomy Research
Laboratory, or NOIRLab.
-
- As long as there are about five
observations in 30 days associated with the same pocket of the sky, the
algorithm can get to work. It's trained on a large dataset that makes it
capable of analyzing as many as 1.7 billion light dots in just a single
telescope image. It is designed to scope out and connect a point of light from
one image of the sky to another one in a different image, and determine whether
both specks represent the same object.
More often than not, that indicates an asteroid moving through space.
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- The scientists scaled their algorithm using
Google Cloud, whose computational heft and data storage services made it easier
for the scientists to test out thousands of orbits of asteroid candidates.
-
- In 2022, the same team of scientists used
THOR to discover 100 asteroids that had been undetected in existing telescope
images. Other teams of astronomers have also leveraged AI to find new
asteroids.
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- Citizen scientists spearheaded training of
an algorithm that led to the discovery of 1,000 new asteroids in archival
images clicked by the Hubble Space Telescope. Last July, a software named
“HelioLinc3D” designed to hunt for near-Earth asteroids found a 600-foot-wide
space rock expected to approach within 140,000 miles of Earth. That's closer
than the average distance between our planet and the moon.
-
- Scientists have so far spotted over 2,000
such "potentially hazardous asteroids" and estimate about 2,000 more
are yet to be discovered. Detecting these space rocks in an effort to aid
planetary defense is one of the tasks of the upcoming Vera C. Rubin Observatory
in Chile, for which the asteroid-hunting HelioLinc3D software was developed.
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- The 8.4-meter telescope, which is scheduled
to start operations in 2025, will take images of the southern sky every night
for at least a decade, each image covering 40-full-moons of area. Scientists
say this cadence, supported by AI-based software like THOR and HelioLinc3D,
could help the observatory find as many as 2.4 million asteroids, double than those now cataloged in its first
six months of operations.
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-
June 23, 2024 ASTEROIDS -
close to Earth? 4511
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