It’s always unnerving to learn that NASA, arbiters of space safety, missed a giant hunk of space rock flying so close to the Earth you almost needed to duck.
Like the asteroid that did a fly-by at just half the distance between the Earth and the moon on Monday of this week.
Unlike the movie Armageddon, we may not have enough warning for Bruce Willis and friends to get on a rocket and go blow it up before it hits us.
Monday at 7:47 A.M. EST, an asteroid passed by Earth at about half the distance between our planet and the Moon—roughly 119,500 miles, reports Mike Wall at Space.com. The space rock, dubbed 2017 AG13 was on the “smallish” size as far as asteroids go, Wall reports, thought to be between 36 and 111 feet wide.
But the most interesting thing about this near miss is that astronomers didn’t spot the space rock till Saturday. It managed to fly under the radar for so long because the asteroid was fairly dim and moving fast (roughly ten miles per second). But just days before it passed us by, researchers at University of Arizona’s Catalina Sky Survey caught a glimpse.
The IBTimes described it as “the size of a house.”
The near miss of a PHA (Potentially Hazardous Asteroid) especially alarming when:
A) it’s large
B) it’s coming close to Earth.
C) we didn’t even realize it was there.
A little bit of information about asteroids
Asteroids originate far out in the cold, dark depths of the solar system. These lumps of rock vary in size from football to mountain-sized roughly round ball. They carry on their way through the vacuum of space unless something comes along that changes their trajectory.
Moving an asteroid from one path or direction to another can happen in a couple of ways:
- It bumps into another asteroid or a lump of space debris and, surviving the impact, either intact or in pieces it “bounces” off in another direction.
- It gets caught in the gravitational pull of a much more massive celestial body and settles into an orbit around that body.
Impact craters all over the Earth and the moon testify to the fact that we’ve been hit on many occasions. And unfortunately, the experts don’t always see it coming.
A large strike can cause wildfires, massive destruction, and even tsunami if they hit the ocean.
The damage posed by a direct hit can be affected by the composition of the object itself. One made predominantly of iron would hurtle through our atmosphere relatively unchanged and create an enormous amount of damage when it impacted. One with less iron and more rock usually explodes in the atmosphere.
And as you’ll learn, one that explodes before it hits the Earth can wreak a lot of damage, too. (If you haven’t signed up for updates like this one, go here. It’s free and you get 9 PDFs with your subscription.)
How many large asteroids are detected?
An article on The Daily Sheeple in April 2014 stated:
The Nuclear Weapons Test Warning Network has detected 26 multi-kiloton asteroid hits since 2001. Based on these figures, asteroids impacting with Earth are 3-10 times more common and more likely in the future than scientists previously believed.
Luckily for us these hits have been in remotely populated areas. That however is nothing more than luck…and if impacts of that magnitude continue to bombard Earth then one day soon we will find that our luck has run out…
A few Asteroid vs. Earth events…
Back in 2013, a previously unknown lump of rock burned up over the town of Chelyabinsk in Russia. This “small” event injured more than 1,000 people and shattered windows across a six-city wide area. This asteroid was probably made up of more rock and less iron, as described above.
Last September NASA missed a meteor that slammed into the sea off the coast of Australia. I wrote at the time:
NASA, tasked with protecting us from incoming threats from space, failed to spot a meteor that slammed into the ocean off the coast of Australia yesterday (Sept. 16). Police received hundreds of calls as people watched a fireball move across the sky above the Gladstone area of Queensland.
Thankfully, this one landed in the ocean without causing a tsunami. With 7/10ths of the planet covered in ocean, this is statistically the most likely place for them to land.
The next story is genuinely alarming because the asteroid didn’t even have to hit the Earth to cause massive damage.
It happened in 1908 above Tunguska in Siberia,
At 7:17 AM on the morning of June 30, 1908, a mysterious explosion occurred in the skies over Siberia. It was caused by the impact and breakup of a large meteorite, at an altitude roughly six kilometers in the atmosphere. Realistic pictures of the event are unavailable. However, Russian scientists collected eyewitness accounts of the event. I believe that we now know enough about large impacts to “decode” the subjective descriptions of the witnesses and create realistic views of this historic asteroid impact as seen from different distances.
You can get a sense of the magnitude of this event by comparing observations made at different distances. Seismic vibrations were recorded by sensitive instruments as much as 1000 km (600 mi) away. At 500 km (300 mi), observers reported “deafening bangs” and a fiery cloud on the horizon. About 170 km (110 mi) from the explosion, the object was seen in the cloudless, daytime sky as a brilliant, sunlike fireball; thunderous noises were heard. At distances around 60 km, people were thrown to the ground or even knocked unconscious; windows were broken and crockery knocked off shelves. Probably the closest observers were some reindeer herders asleep in their tents in several camps about 30 km (20 mi) from the site. They were blown into the air and knocked unconscious; one man was blown into a tree and later died. “Everything around was shrouded in smoke and fog from the burning fallen trees.” (source)
Professor Oleg Malkov, Head of the Star Clusters Physics Department at the Russian Science Academy Institute of Astronomy has said that the Tunguska Event was caused by a space rock just 65 yards across (60 meters).
Can you imagine if that had exploded over New York? Or LA? Or London?
The results would have been devastating.
As for something ten times that size, a perfectly normal space phenomenon, catastrophic doesn’t even begin to cover it.