There are millions of space rocks known as asteroids in our solar system. These objects,
which range in size from a few meters to hundreds of kilometers, were mostly left over
from the formation of our planets 4.6 billion years ago. They are building blocks that never
developed into full-fledged worlds. Yet another factor that has scientists watching them closely
is the potential for disaster should one of them collide with Earth. In fact, NASA Chief has issued
dire warnings as asteroids approach the Earth, demonstrating the gravity of the situation. This
is why NASA launched its DART Mission. A large majority of asteroids larger than one kilometer
in size have been accounted for, and their orbits have been verified as safe for Earth, but smaller
asteroids are monitored much less closely. Even a ten-meter-wide rock can cause significant
damage if it strikes a populated area. The time between spotting a new asteroid and it hitting
our planet can be a matter of days and such an asteroid is known as an 'imminent impactor'.
The main asteroid belt, which lies between Mars and Jupiter, is the source of the vast majority
of asteroids. The current asteroid count by NASA exceeds one million. Asteroids orbit the sun
in highly flattened, or "elliptical" circles, frequently rotating erratically, tumbling and
falling through space. Many large asteroids are accompanied by one or more small moons. An example
of this is Didymos, a half-mile (780 meters) wide asteroid that is orbited by the moonlet Dimorphos
which measures just 525 feet (160 m) across. They are also known as "minor planets" and can
range in size from the largest known example, Vesta, which has a diameter of around 326 miles
(525 kilometers), to bodies as small as 33 feet (10 meters). Vesta recently snatched
the "largest asteroid title" from Ceres, which NASA now classifies as a dwarf planet. Asteroids
come in a variety of shapes, ranging from near spheres to irregular double-lobed peanut-shaped
asteroids like Itokawa. The majority of asteroid surfaces have impact craters from collisions with
other space rocks. Though the vast majority of asteroids are believed to be in the asteroid belt,
NASA claims that the massive gravitational influence of Jupiter, the solar system's
largest planet, can send them hurtling through the inner solar system and thus towards Earth.
Near-Earth asteroids, or NEAs, are a new group of asteroids that scientists are paying special
attention to due to their proximity to the Earth. NEAs, as the name implies,
orbit the sun at nearly the same distance as the Earth. These objects are classified according on
how their orbits compare to Earth's. For example, Amor asteroids have orbits that approach Earth's
path but only move between Earth and Mars, whereas Apollo asteroids have Earth-crossing orbits but
spend the most of their time beyond the planet's path. Aten asteroids cross Earth's orbit but spend
the majority of their time within it, while Atira asteroids are near-Earth asteroids with
orbits that are confined within Earth's orbit. Certain near-Earth asteroids are also known as
"potentially hazardous asteroids," or PHAs; these rocks are less than 4.65 million miles
(7.48 million kilometers) from Earth's orbit and are bigger than 500 feet (140 meters) in
diameter. As of 2021, scientists had detected approximately 27 000 near-Earth asteroids,
with slightly under 10,000 of those having diameters bigger than 500 feet.
The concept of asteroids crashing into the Earth is one that has been overused and exploited by
filmmakers. However, asteroids are a real hazard to our planet; they can wreak significant damage
or perhaps wipe out all life on Earth. Actually, the Earth has already been hit by asteroids on
several occasions; the Chicxulub event is one of the worst in our planet's history. This asteroid,
with a diameter of 10 to 15 kilometers (six to nine miles), crashed with Earth 65 million
years ago near what is now Mexico. The collision annihilated 70% of all life on Earth, including
dinosaurs. A collision of that scale would have had disastrous repercussions, and the geological
record provides some insight into what occurred. Because the asteroid collided with water,
mega-tsunamis smashed into Southeast Mexico, Texas, and Florida, as well as up a shallow
internal ocean that covered what is now the Great Plains. The blast would have thrown an asteroid
into Earth fragments far enough away that they would have briefly exited the atmosphere before
reentering it. Upon re-entry, all of this debris, like millions of shooting stars, would have been
heated to incandescence, scorching the Earth's surface and sparking wildfires. It's possible
that the world's forests were all destroyed. Massive shock waves would have generated worldwide
earthquakes and possibly volcano eruptions in the meanwhile. A cloud of superheated dust,
ash, and steam would have burst from the crater as the impactor plunged underground in less than
a second, covering the whole Earth's surface for up to a decade and creating a terrible
environment for life. More crucially, the dust might have persisted in the sky for many years,
shutting out the light, interfering with plant photosynthesis, on which the entire food chain is
dependent, and reducing the earth's temperatures. But the asteroid impact that caused the Vredefort
crater in South Africa was even more violent. This at least 20-kilometer-wide asteroid slammed into
Earth roughly 2 billion years ago. The collision created a surface crater 40 kilometers deep and
100 kilometers broad. As the granite below began to rebound and the valves cracked,
the crater grew and then shrank nearly immediately after impact. Scientists believe the Vredefort
crater was between 180 and 300 kilometers wide when the rebound and collapse ended. However,
erosion over more than 2 billion years narrowed the entrance to what you see today. The uplift
in the impact center, on the other hand, was so tremendous that it turned a 25-kilometer portion
of the earth's crust on edge. The several strata of upturned rock eroded at different speeds,
resulting in the concentric pattern observed today. The Vredefort asteroid was likely double
the size of the dinosaur-killing Chicxulub, according to new assessments of the original
size of the Vredefort crater. It might also have been travelling significantly faster,
increasing the severity of its impact and potentially making it the single biggest
energy release event in Earth's history. It might have reached speeds of up to 56 000 miles per hour
(90 000 kilometers per hour). However, unlike the Chicxulub impact, the Vredefort impact left
no record of mass extinction or forest fires because there were only single-celled living
forms and no trees 2 billion years ago. The impact, however, would have been bigger on
the global climate than the Chicxulub impact. Not all asteroid collisions occurred millions
of years ago. In 1908, an asteroid or comet with a diameter of roughly 30 meters entered
the atmosphere and exploded above ground in Tunguska, Russia. The explosion killed around
80 million trees, covering an area of 2150 square kilometers (830 square miles). This explosion
was estimated to be 1,000 times more powerful than the atomic bomb detonation in Hiroshima.
If this had occurred over a city, it would have been entirely devastated. Fortunately,
it happened in a remote part of Siberia, and no one was believed to have died.
But is there really a chance that an asteroid may hit Earth? NASA has warned us several times about
asteroids heading our way. The asteroid 2022 AP7, for example, was discovered by an international
team of scientists using a camera designed to study dark energy in the universe. The 2022 AP7
orbit overlaps the Earth's path around the sun, approaching as close as 4.4 million miles to the
planet—uncomfortably close by cosmic standards. As a result, the 2022 AP7 is the largest possibly
dangerous asteroid detected in the last eight years. with a diameter ranging from 1.1 to 2.3
kilometers 2022 AP7 is the largest PHA discovered since 2014, and it is anticipated to be among the
top 5% of all PHAs discovered. And now comes the truly awful part: any asteroid larger than
one kilometer in size is classified as a planet killer. If such an object collided with Earth,
the resulting dust and pollution would be deadly to life as we know it, lingering in the atmosphere
for years. The lack of sunlight would cause the Earth's surface to cool dramatically,
resulting in a global extinction event unmatched in millions of years. As a result, after the
asteroid was discovered in January, additional observatories investigated its velocity,
and other astronomers detected it in previous photographs. This data collection indicated that
it will not be approaching Earth for at least the next century, if not much longer, but this does
not imply we are secure. The gravitational pull of solar system objects, including our own planet,
ensures that Earth-crossing asteroids do not dance in the same pattern indefinitely. The asteroid
2022 AP7 is no exception. As it traverses Earth's orbit, this asteroid will become more apparent in
the sky, going closer and closer to where the Earth truly is. The orbit of this asteroid,
however, is not its most significant aspect because we are safe for many generations. The
discovery of 2022 AP7 is most intriguing because it hints that further gargantuan
asteroids veiled by the sun's glare are still undiscovered. This is why astronomers seeking
for PHAs focus on boulders 460 feet in diameter. They number in the tens of thousands, and only
approximately half of them have been identified. Another potentially hazardous asteroid is 2001
CB21, a massive asteroid believed to be the size of the Golden Gate Bridge that is moving towards
Earth and is expected to make a close approach. The asteroid has been classed as "potentially
hazardous" by NASA because it will pass within 0.69 AU of Earth. While that distance may appear
to be great on the cosmic scale, it is literally in our backyard. The possibly hazardous asteroid
has a diameter of approximately to 1.3 kilometers (4265 ft). The asteroid was discovered by Italian
Virtual Telescope Project astronomer Gianluca Masi at a distance of more than 21.5 million
miles from Earth. If CB21 collided with Earth, the consequences would be disastrous, but how awful
would they be? According to study, a collision between an asteroid larger than 130 meters in
diameter and Earth would discharge energy at least a thousand times that of the first atomic bomb.
Something considerably larger, such as the 300-meter-wide asteroid Apophis, might wipe out
a whole continent. A kilometer-wide asteroid like the 2001 CB21 may devastate the entire planet.
Let us know what you think about asteroids hitting the Earth in the comments section below.