A "gigantic" asteroid the size of the Empire State Building sped "towards Earth" in early January 2020.

(Photo : MasterTux on Pixabay)

At least, that's how Sputnik, the Russian government-funded news outlet, described it. The fact was that asteroid 2019 UO will pass us safely on January 10 at a distance of 2,808,194 miles, as reported in the article following the frightening title (4,519,351 kilometers). That's about 12 times the distance between the Earth and the Moon. Every night, people hardly imagine the Moon racing toward their house, let alone something 12 times farther away.

However, this is the kind of phrase you'll see a lot in places that adore frightening asteroid stories. The deceptive headlines and stories make use of the terms scientists use to describe space objects and the meanings some of those terms have in ordinary English.

Near Earth Objects

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The words "near-earth object" (NEO) and "potentially hazardous asteroid" (PHA), for example, are astronomical terminology that is used to describe asteroids that have extremely specific meanings. For example, if an asteroid approaches Earth at a distance of 4.6 million miles and has a particular brightness, it is classified as a PHA. This is essentially simply astronomers' method of compiling a massive list of things to keep an eye on. There is no additional assessment of each asteroid to establish how "possibly dangerous" it is before it is labeled as such.

NEOs are a subset of a larger group. So, for example, everything between that point and the sun might potentially be deemed a NEO if you were to leave Earth and go in the direction of Mars' orbit around the sun, then halt when you're approximately 85 percent of the way there.

Related Article: Giant "Mega-Comet", First Observed in 2014, Will Finally Be Passing by the Solar System


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(Photo : Wikimedia Commons)

It may seem odd to non-scientists to refer to an asteroid as "close" when it is farther away from us than any person has ever traveled. However, when dealing with the mind-boggling vastness of the cosmos, as astronomers do, it makes perfect sense. The same may be said for those PHAs. Although most PHAs are not truly potential threats in our lifetimes, it makes it reasonable to term them such in light of the vastness of space.

So the next time you read a headline warning about a "behemoth space asteroid threatening Earth," you may need to find other sources to figure out how concerned you should be.

Unnecessary Alarms

Many media sites began raising the alarm in the second part of 2019 about the arrival of asteroid 2006 SF6, which made a near-Earth encounter on November 21. Some of the stories made it sound like a dangerous rock was coming our way, so many checked the European Space Agency's Risk Page about a week before it was to fly by.

"All objects for which a non-zero impact probability has been detected," according to the ESA.

Nothing showed up when they searched the page for 2006 SF6 and its catalog number, 481394, to acquire the complete risk list. This possible planet-killer does not feature on the list of the 991 most dangerous space objects.

Then they examined the Center for Near-Earth Studies at NASA's Jet Propulsion Laboratory's public database of near encounters. A quick search turned up 2006 SF6. With an estimated diameter of 919 feet to 2,690 feet, it is certainly a giant (280 meters and 820 meters).

On impact, this skyscraper-sized space rock may do significant damage. Its close-approach distance, on the other hand, was stated as 11.23 lunar distances. So it's exactly as it sounds: more than 11 times the distance between the Earth and the Moon, or roughly 2.7 million miles (4.3 million kilometers). Sorry, but this colossus poses no threat to the planet.

Should we be Worried?

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The argument isn't that you shouldn't be concerned about asteroids. On the contrary, the threat of an object from space colliding with Earth is genuine, as countless dinosaur remains and the rest of the geologic record show. But it's the goods that aren't yet in our catalogs that pose the greatest threat.

The most major impact of the previous century occurred in 2013, when a meteor collided with the atmosphere above Russia, causing a shock wave that broke hundreds of windows in Chelyabinsk. Before it burst in the sky, the space rock had never been seen before.

Astronomers' technology and procedures have advanced to the point that new NEOs are found daily. This includes some things that are extremely close to Earth. However, they are usually so small that they would most likely burn up in the atmosphere if they hit us, as one did in 2018.

Also Read: Potential Faster-Than-Light-Space Travel Facts: Alcubierre's Warp, the Key To Interstellar Travels?

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