Several asteroids have grazed past the Earth, some have hit the surface, and many more will follow in their ‘footsteps’ in the future. Despite hearing about them numerous times, an asteroid approach always keeps us on the edge of our seats — after all, there’s always the possibility of a monstrous planetoid crashing into our planet and smashing it to smithereens.
However, this is why space agencies and astronomers are constantly on the lookout for the next asteroid whose path may cross that of the Earth.
During one such survey, astronomers using the Dark Energy Camera (DECam) at Chile’s Cerro Tololo Inter-American Observatory discovered three near-Earth asteroids (NEA) hidden in the Sun’s glare. These space rocks have been given the designations 2022AP27, 2021 LJ4, and 2021 PH27.
The 2022AP27 is the most concerning of the three. It is the largest space object detected in the last eight years with an orbit that may cross the path of the Earth, measuring 1.5 kilometers in diameter.
So far, only two such monstrous asteroids with diameters greater than one kilometer have been discovered, though more may be lurking in the shadows.
The other two, 2021 LJ4 and 2021 PH27, are in a safe location. The latter, on the other hand, may pique interest as the closest known asteroid to the Sun, with a surface hot enough to melt lead. Asteroids farther from the Sun are easier to spot; the real challenge is detecting near-Earth asteroids. This is because celestial rocks that lurk in the inner solar system, within the orbits of Earth and Venus, become obscured by the bright background provided by the sunrays.
Because of their difficult location, astronomers have only two 10-minute daily intervals during twilight to capture these elusive rocky bodies. The difficulty in observing them is exacerbated by distortions caused, ironically, by the thick layer of Earth’s atmosphere.
Asteroids farther from the Sun are easier to spot; the real challenge is detecting near-Earth asteroids. This is because celestial rocks that lurk in the inner solar system, within the orbits of Earth and Venus, become obscured by the bright background provided by the sunrays.
“Because of the difficulty of observing near the glare of the Sun, only about 25 asteroids with orbits completely within Earth’s orbit have been discovered to date,” said Scott S. Sheppard, an astronomer at the Carnegie Institution for Science’s Earth and Planets Laboratory.
However, the astronomers are up to the task, thanks to the Dark Energy Camera, a programme of the National Science Foundation USA’s NOIRLab. The DECam allowed researchers to capture deep and wide field images of faint space objects, as well as reveal the three aforementioned NEAs.
When combined with the recent success of NASA’s Double Asteroid Redirection Test (DART), such precise technology has prepared our planet for future impact events.