Astronomer Scott Sheppard has written a Perspective article titled “In the glare of the Sun” in the journal Science.
Sheppard is an astronomer at the University of Hawaii’s Institute for Astronomy and believes scientists need to look more closely for near-Earth objects (NEOs) in space in the direction of the Sun. He notes that most observations are often made from the night sky, but NEOs like asteroids that pose a potential threat to Earth could be hiding between the Sun and Earth, some of which have recently been discovered.
One of these near-Earth asteroids (NEAs) was found within the orbit of Venus, and another was discovered with the shortest known orbital period around the Sun. The night sky is observed more often, since the sunlight does not overwhelm the observations. However, Sheppard notes that the technology now exists to survey the sky in the direction of the Sun during twilight hours.
The “twilight telescope” surveys that Sheppard and others may conduct in the future will help find “city killers,” NEOs at least 460 feet (140 meters) in diameter. Current models indicate that about 90% of “planet killer” NEOs have been found; however, only about half of the city’s killers have been found.
“The main reason we haven’t found all the ‘city killers’ is simply because we haven’t been looking at the sky at the same depth for years and years to find them,” Sheppard told Space.com.
“We’re doing a full survey looking for anything moving around the orbit of Venus, which is a place we haven’t studied very deeply in the past with anything other than small one-meter telescopes. It’s pretty hard to do and larger telescopes generally don’t have a very large field of view, so you can’t cover much of the sky,” Sheppard said.
You can read Sheppard’s piece here.