Planet-killing asteroid discovered hidden behind the Sun's glare
Astronomers detected three near-Earth asteroids that remained hidden behind the Sun's glare. One of them is the largest object of potential risk to Earth that has been discovered in the last eight years.
The asteroids are part of a group that lie within the orbits of Earth and Venus, but are very difficult to detect because the Sun's brightness shields them from telescope observations.
To avoid the glare of the Sun, astronomers took the opportunity to make their observations during the brief twilight window. An international team observed the space rocks using the Dark Energy Camera (DECam) on the Victor M. Blanco 4-meter telescope at the Cerro Tololo Inter-American Observatory in Chile.
Their findings were published Monday in the academic journal The Astronomical Journal.
One of the asteroids, called
2022 AP7, is 1.5 kilometers wide and has an orbit that could bring it close to Earth's trajectory in the future. But it's hard for scientists to know when that would happen.
"Our twilight survey looks for asteroids in the orbits of Earth and Venus," explained the study's lead author, Scott S. Sheppard, an astronomer at the Earth and Planets Laboratory of the Carnegie Institution for Science in Washington, in a statement.
"So far we have found two large near-Earth asteroids that are about 1 kilometer in diameter, a size for which we call them 'planet killers.'"
The scientists determined that the asteroid crosses Earth's orbit, but does so when our planet is on the opposite side of the Sun. A pattern that will continue for centuries, as the asteroid takes five years to complete one orbit around the Sun. But, over time, the asteroid's orbital motion will become more synchronized with that of the Earth. Scientists do not know the asteroid's orbit precisely enough to say how dangerous it might become in the future. For now, however, "it will stay well away from Earth," Sheppard said.
The other two asteroids, 2021 LJ4 and 2021 PH27, are in much safer orbits that do not pose a risk to Earth.
Astronomers are intrigued by 2021 PH27, however, because it is the closest known asteroid to the Sun.
As the space rock approaches our star, its surface reaches temperatures high enough to melt lead.
During twilight, astronomers still face the complications of having the Sun's brightness as a backdrop. And to search the inner solar system, their telescopes must focus close to the horizon, which means they have to look through Earth's thick atmosphere and its defocusing effects.
If things seem complicated for ground-based telescopes, observations of the inner solar system are impossible for space telescopes like Hubble and James Webb because the heat and intense light from the Sun could burn their instruments. For that reason, both space observatories point away from the star.
Los astrónomos detectaron tres asteroides cercanos a la Tierra que permanecían ocultos tras el resplandor del So, uno de ellos es potencialmente peligroso.
cnnespanol.cnn.com
www.imo.net
http://spmn.uji.es/ESP/SPMNlist.h
C. Alcaraz @Astrocorbera2 , Corbera de Llobregat
alertamundialinfo.com
