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New telescope will scan the sky for asteroids on a collision course with Earth



This article was originally published on The Conversation. The publication contributed the article to Space.com's Expert Voices: Op-Ed & Insights.

At sunrise on February 15, 2013, an extremely bright and otherworldly object roamed the sky over Russia before it exploded over 97,000 feet above the Earth's surface. The resulting explosion damaged thousands of buildings and injured nearly 1,500 people in Chelyabinsk and the surrounding area. While this sounds like the first scene of a science-fiction movie, this intruder was not an alien spaceship attacking humanity, but a 20-meter-wide asteroid that collided with Earth.

What's worrisome was that no one had any idea that this 20-meter asteroid existed until it entered the Earth's atmosphere that morning.

As an astronomer, I study objects in the sky that change in brightness over short time scales ̵

1; observations that I use to discover planets around other stars. Much of my research is understanding how we can better plan and operate telescopes to monitor an ever-changing sky. This is important because the same telescopes with which I explore other star systems also serve to help my colleagues discover objects in our own solar system, like asteroids on a collision course with Earth.

The US government takes the threat of an asteroid collision seriously. In Section 321 of the NASA Authorization Act of 2005, Congress called on NASA to develop a NEO search program. NASA's mission was to identify 90 percent of all NEOs over 140 meters in diameter. Currently, they estimate that three quarters of the 25,000 PHAs still need to be found.

To achieve this goal, an international team of hundreds of scientists, including myself, completes the construction of the Large Synoptic Survey Telescope (LSST). in Chile, which will be an important tool to point out PHAs.

  Exterior of the Large Synoptic Survey Telescope, which is still under construction. Sublocation Cerro Pachón, Chile.

Exterior of the Large Synoptic Survey Telescope, which is still under construction. Cerro Pachón Sublocation, Chile

Credit: LSST Project / NSF / AURA, CC BY-NC-SA

With significant financial support from the US National Science Foundation, LSST will seek out the same skyline in its 10-year mission PHAs hourly distance to objects that have changed their position. Anything moving in an hour must be so close that it is in our solar system. Teams led by researchers from the University of Washington and JPL have both produced simulations demonstrating that LSST alone will be able to find approximately 65 percent of the PHAs. When we combine LSST data with other astronomical surveys such as Pan-STARRS and the Catalina Sky Survey, we believe we can help detect 90 percent of the potentially dangerous asteroids.

  A photo and a baseline rendering mix with a view of the completed exterior building from the road leading to the location.

A photo and a floor plan rendering mix showing a view of the completed exterior building from the street leading to the construction site.

Credit: LSST Project / NSF / AURA, CC BY-NC-SA

Both the Earth and these asteroids orbit the Sun only in different ways. The more observations made by a given asteroid, the more accurately its orbit can be mapped and predicted. The biggest priority then is to find asteroids that could collide with Earth in the future.

If an asteroid is on a collision course for hours or days before it occurs, the Earth will not have many options. It's like a car that suddenly pulls out in front of you. There is little that you can do. However, if we find these asteroids years or decades before a potential collision, we can use spaceships to push the asteroid enough to change its path so that it and the earth do not collide.

But easier said than done, and currently no one really knows how well an asteroid can be diverted. There have been several proposals for missions by NASA and the European Space Agency to do so, but so far they have not passed through the early stages of mission development.

The B612 Foundation, a private nonprofit group, is also trying to raise money privately for a mission to divert an asteroid, and they may be the first to try it if the government's space programs fail to do so. Squeezing an asteroid sounds like a weird thing, but if we find an asteroid on a collision course with Earth someday, it may be this knowledge that will save humanity.

Michael B. Lund, Post-Doctoral Student, Department of Physics and Astronomy, Vanderbilt University

This article was originally published on The Conversation. Read the original article. Follow all the questions and debates of Expert Voices – and become part of the discussion – on Facebook, Twitter and Google +. The views expressed are those of the author and do not necessarily reflect the views of the publisher. This version of the article was originally published on Space.com. [194559002]


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