Astronomers on the lookout for small asteroids that may melt a city or large ones that could sterilise Earth’s surface have identified a new possible hazard. But there is no immediate cause for concern; it will be many generations before it poses a threat to our world.
Observing the sunlight glinting off the surfaces of undiscovered space pebbles is necessary for detecting them. However, some asteroids reside in regions of the sky where the sun’s glare obliterates them, and they vanish from view like embers fluttering in front of a thermonuclear inferno.
An worldwide team of astronomers repurposed a camera built to explore the universe’s famously elusive dark matter in order to search for asteroids obscured by abundant sunlight in the last year. Monday, the researchers revealed the finding of three new light-downed projectiles, based on a study initially published in September in The Astronomical Journal.
One of them, 2022 AP7, is about a mile long, and its orbit overlaps Earth’s path around the sun, coming as close as 4.4 million miles to Earth – an uncomfortably close distance by cosmic standards (but far further than Earth’s moon). This makes 2022 AP7 “the biggest potentially dangerous asteroid discovered in the previous eight or so years,” according to Scott Sheppard, an astronomer at the Carnegie Institution for Science in Washington, D.C., and the study’s author.
After the asteroid was found in January, more observatories investigated its velocity, and other astronomers detected it in previous photographs. This data collection revealed that it will not reach Earth within the next century, and maybe for much longer.
Tracy Becker, a planetary scientist at the Southwest Research Institute who was not involved in the research, stated, “The likelihood of an impact occurring in the near future is quite low.”
However, the gravitational pull of objects across the solar system, including our own planet, assures that Earth-crossing asteroids will not continue to dance in the same manner forever. The asteroid 2022 AP7 is similar. Dr. Sheppard said, “Over time, this asteroid will become more visible in the sky as it crosses Earth’s orbit closer and closer to its true location.”
Alan Fitzsimmons, an astronomer at Queen’s University Belfast who was not involved with the research, said that “in the far future, within the next few thousand years, it might become an issue for our grandchildren.”
What if, in the most worst of scenarios, 2022 AP7 eventually strikes Earth?
As humans are safe for many generations, the orbit of this asteroid is not its most notable characteristic. The comparatively big size of 2022 AP7 is intriguing, according to Cristina Thomas, a planetary scientist at Northern Arizona University who was not involved in the research. Its presence implies that more elephantine asteroids, hidden from view by the sun’s brightness, remain unsettlingly unidentified.
Today, scientists searching for potentially dangerous asteroids — those that pass within 4.6 million miles of Earth and are too large to be consumed by our atmosphere without incident — concentrate on locating boulders measuring around 460 feet wide. They presumably number in the tens of thousands, and less than half have been recognised. They might cause havoc on a national scale. Such risks prompted NASA and other space agencies to design planetary defence missions, such as DART, the spacecraft that successfully altered the orbit of a minor, non-threatening asteroid in September.
Several certainly lurk about Mercury and Venus. Dr. Thomas said that it is “very difficult” to find objects within the Earth’s orbit with our existing discovery telescopes. During the most of the day, the sun blinds Earth’s telescopes, limiting object hunting to the few minutes around dusk.
The scientists that discovered 2022 AP7 used the Dark Energy Camera on the Chilean Vctor M. Blanco 4-meter Telescope to circumvent this constraint. In addition to being able to study vast expanses of the sky, it is also sensitive enough to detect faint objects obscured by sunlight. So far, the camera has discovered two additional near-Earth objects: a planet-killer-sized rock whose orbit never crosses Earth’s but brings it closer to the sun than any other known asteroid, flambéing its surface at temperatures high enough to melt lead, and a smaller, country-killer-sized rock that poses no threat.
The Near-Earth Object Surveyor mission will ultimately supersede the capabilities of the twilight survey. This Earth-orbiting infrared observatory will gaze into the sun’s brightness and discover the majority of hazardous asteroids overlooked by previous surveys.
Dr. Thomas said, “We want to do everything possible to avoid being startled.” This is why these surveys exist: to locate Earth-impacting asteroids many lifetimes in advance so that we may drive these monsters back into the shadows with energetic prods or nuclear explosions.