Thursday , September 24 2020

How to find out if the "killer" asteroid will collide with Earth



Artist's impression of an asteroid slamming into Greenland's ice sheet.

Carl Toft

Do a simple Google News asteroid search, and the headlines call you.

"NASA warns 2-mile-wide asteroid killer heading for Earth," or "… date of potential impact in 2022" or "Asteroid tsunami … could destroy US coast" . And, of course, "… a monster rock can cross the Earth at 17,000 kilometers per hour."

These are just a few of the stories that emerged in the last week, mostly in the tabloids in the UK that really want scary stories of asteroids.

If you read the previous sensational headlines, you usually find accurate information about an asteroid that will definitely not hit the Earth any time soon. That killer planet 2 kilometers wide? Did not miss the 1.4 million miles. It is about 6 miles from the moon. You literally have to be more concerned about the moonlighting in your house.

Headlines and stories make use of words that scientists use to talk about space objects and connotations that some of those words have in everyday language.

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For example, the terms "near-Earth object" (NEO) and "potentially dangerous asteroid" (PHA) are astronomical terms used to categorize objects with very specific definitions. If the asteroid is 4.6 million miles from Earth and has some brightness, it makes the PHA list. This is really just a way for astronomers to create a very large catalog of objects worth keeping an eye on. No other estimate was made by each asteroid to determine how "potentially dangerous" it was before it was labeled.

NEOs fall into an even broader category. If you were to leave Earth and travel in the direction of Mars' orbit around the sun, then stop when you are about 85 percent of the way to the Red Planet, everything between that position and the sun can technically be considered NEO.

To non-scientists, it may seem strange to call an asteroid farther away from us than man has ever traveled "near", but it certainly makes sense when dealing with the universe's large-scale reason, as astronomers do. The same is true for those "potentially dangerous asteroids". It makes sense to call them that in the context of the vastness of space, although most PHIs are not actually potential hazards in our lives.

So, the next time you see a headline screaming about how "the space rock of the bahamas is threatening the earth", you can check out the same sources that I do to determine exactly how much you should care. In fact, I'll take it as an example of specific behaviors.

Several outlets have already begun to sound alarms about the approach of the 2006 SF6 asteroid, which is set to gain close access from Earth on November 21. It sure sounds like a risk rock going through some of the titles, so I check the European Space Agency's risk page.

The ESA maintains a list of "all items for which there is no probability of impact being detected".

When I click to get a complete list of risks and search the site for 2006SF6 and its catalog number, 481394, nothing comes up. This potential pummel seems not to have made the list of 991 most endangered space objects.

Next, I'm checking the public database of near-misses maintained by the NASA Aircraft Mobility Laboratory's Center for Near-Earth Studies. The search is entitled SF6 in 2006. It is really a bit of bahmot, with an estimated diameter of between 919 and 2,690 feet (280 and 820 meters).

This skyscraper-sized space rock can cause real impact. But its distance is closely stated as 11.23 lunar distances. That's what it sounds like: over 11 times the moon, or about 2.7 million miles (4.3 million kilometers). Sorry, but this behemoth definitely does not endanger the Earth.

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My point, though, is not that you don't have to worry about asteroids. How much dinosaur fossils and the rest of the geological record Tell us, the threat of being impacted by an object in space is very real. But the main threat comes from items still missing in our catalogs.

The most significant impact of the last century occurred in 2013 when a the meteor impacted the atmosphere over Russia, creating a shock wave that destroyed thousands of windows. That space rock had not been spotted before before it exploded in the sky.

The technologies and techniques used by astronomers have improved to such an extent that new NEOs are discovered virtually every day. This includes some objects, actually close to the Earth, although they tend to be so small, they are likely to ignite in the atmosphere if they affect us, like one done in 2018.

But we still have blind spots, as the impact in 2013 demonstrates, so the imperative to move forward is not to unleash some harmless asteroids, but to devote more resources to continue refining the sky and completing it our catalog, so we are not caught again surprisingly.

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