'Tunguska'-Size Asteroid Makes Surprise Flyby of Earth

Our fragile society upon our Fragile Earth had an encounter recently which would have had quite the impact:

An asteroid similar in size to one that exploded more than 100 years ago in Russia's Tunguska region in Siberia gave Earth a close shave on Sunday (April 15), just one day after astronomers discovered the object.

The asteroid, designated 2018 GE3, made its closest approach to Earth at around 2:41 a.m. EDT (0641 GMT), whizzing by at a distance of 119,400 miles (192,000 kilometers), or about half the average distance between Earth and the moon, according to NASA's Center for Near Earth Object Studies (CNEOS).

By Hanneke Weitering, Space.com Staff Writer | April 16, 2018 01:00pm ET



This would not be a global event, but it would make for a catastrophe anywhere nearby if it should intersect coordinates with Earth:

"If 2018 GE3 had hit Earth, it would have caused regional, not global, damage, and might have disintegrated in the atmosphere before reaching the ground," SpaceWeather.com reported. "Nevertheless, it is a significant asteroid, illustrating how even large space rocks can still take us by surprise. 2018 GE3 was found less than a day before its closest approach."

Even disintegrating before impact would not necessarily prevent damage from occurring in the are in which such an event took place. The Tunguska event mentioned in the title is thought to have been an air burst event and the damage wrought there was substantial. A similar such happening above any major metropolitan area would make for very bad day indeed.

With an estimated diameter of 157 to 361 feet (48 to 110 meters), asteroid 2018 GE3 has about three to six times the diameter of the space rock that penetrated the skies over Chelyabinsk, Russia in February 2013, causing some 1,500 people to seek treatment for injuries, mostly from flying glass.

Asteroid 2018 GE3, an Apollo type earth-crossing asteroid, was flying through space at 66,174 miles per hour (106,497 km/h).

If the asteroid had entered our atmosphere, a great portion of the space rock would have disintegrated due to friction with the air. However, some of an asteroid this size might have gotten through to Earth’s surface, and an asteroid this big is capable of causing some regional damage, depending on various factors such as composition, speed, entry angle, and location of impact. It might make you feel better (or worse) to know that asteroids enter Earth’s atmosphere unnoticed on a fairly regular basis.

Asteroid buzzed Earth this weekend - Earthsky

Element Value Uncertainty (1-sigma) Units
e .8281163146829342 0.00028412
a 1.84908249201133 0.0022811 au
q .3178271131821713 0.00013335 au
i 8.738751045190504 0.0050847 deg
node 25.41161154039496 6.9324e-05 deg
peri 300.1649091336848 0.00093555 deg
M 333.9652537740355 0.053513 deg
tp 2458266.917680487656
(2018-May-28.41768049) 0.013614 JED
period 918.4020757502265
2.51 1.6995
0.004653 d
yr
n .3919851767603229 0.00072536 deg/d
Q 3.380337870840489 0.0041702 au

JPL Small Body Database

Jeez, imagine this going off over Moscow after the attack in Syria?

We might of had an accidental WW3.

We're all doomed. It's just a matter of time and chance. It'll be interesting to watch the thing come screaming out of the sky in a white-hot explosion of fragments. Hard to decide whether it would be best to just be incinerated in the first blast, or die slowly fighting cannibals in the aftermath. Guess we'll find out.

DB is going to be so disappointed it missed.

Giant Meteor 2018!!

By now, they have found out what really happened at Tunguska ? I mean really, scientifically?

originally posted by: grey580
Jeez, imagine this going off over Moscow after the attack in Syria?

We might of had an accidental WW3.

Or landing on Damascus.... Biblical...

a reply to: Blue Shift

At approximately 18.39166... miles per second, you wouldn't have long to wait. CONUS is a little over 2800 miles West to East, this rock would cross that distance in a little over two and a half minutes.

a reply to: alexpmi

earthsky.org...

June 30, 1908 In a remote part of Russia, a fireball was seen streaking across the daytime sky. Within moments, something exploded in the atmosphere above Siberia’s Podkamennaya Tunguska River in what is now Krasnoyarsk Krai, Russia. This event – now widely known as the Tunguska event – is believed to have been caused by an incoming asteroid (or comet), which never actually struck Earth but instead exploded in the atmosphere, causing what is known as an air burst, three to six miles (5–10 kilometers) above Earth’s surface. The explosion released enough energy to kill reindeer and flatten trees for many kilometers around the blast site. But no crater was ever found.

a reply to: DAVID64

I read up upon it many hours. As you quote, is believed to have been....

Wait... when was Tunguska confirmed to be an asteroid, and when did they suddenly have measurements?

I know it's been postulated that it was a meteor, but I didn't know it was confirmed to the point of being treated as fact... I thought Tunguska was a mystery to some degree.

a reply to: Puppylove

The Chelyabinsk meteor in Russia exploded a bit over 18 miles above the ground and blew out windows, doors and destroyed brick walls. The Tunguska meteor exploded at only 3 - 6 miles. Imagine if the 2013 meteor had been that close to the ground when it exploded over the city.
You'd have another Tunguska.

a reply to: Puppylove

Also, numerous spherules and melt-glass have been produced in atomic explosions (36, 37), including the Trinity detonation in New Mexico in 1945, where the airburst produced spherules similar to those from the Tunguska cosmic airburst in 1908 (8, 38).

Evidence for deposition of 10 million tonnes of impact spherules across four continents 12,800 y ago

a reply to: jadedANDcynical

An asteroid similar in size to one that exploded more than 100 years ago ...

I was just about to correct that, but then I realised it is true.

I didn't use to be true!
I am so old..

Based on the intensity of its reflected sunlight, 2018 GE3 must be 48 to 110 meters wide, according to NASA-JPL. This puts it into the same class as the 60-meter Tunguska impactor that leveled a forest in Siberia in 1908. A more recent point of comparison is the Chelyabinsk meteor--a ~20-meter asteroid that exploded in the atmosphere over Russia on Feb. 15, 2013, shattering windows and toppling onlookers as a fireball brighter than the sun blossomed in the blue morning Ural sky. 2018 GE3 could be 5 to 6 times wider than that object.

If 2018 GE3 had hit Earth, it would have caused regional, not global, damage, and might have disintegrated in the atmosphere before reaching the ground. Nevertheless, it is a significant asteroid, illustrating how even large space rocks can still take us by surprise. 2018 GE3 was found less than a day before before its closest approach.

Check out spaceweather.com.

They have a video up of what it looked like flying by at 0.5 LD from a guy's telescope in Austria!

That video is so cool!

Based on the intensity of its reflected sunlight, 2018 GE3 must be 48 to 110 meters wide, according to NASA-JPL. This puts it into the same class as the 60-meter Tunguska impactor that leveled a forest in Siberia in 1908. A more recent point of comparison is the Chelyabinsk meteor--a ~20-meter asteroid that exploded in the atmosphere over Russia on Feb. 15, 2013, shattering windows and toppling onlookers as a fireball brighter than the sun blossomed in the blue morning Ural sky. 2018 GE3 could be 5 to 6 times wider than that object.

If 2018 GE3 had hit Earth, it would have caused regional, not global, damage, and might have disintegrated in the atmosphere before reaching the ground. Nevertheless, it is a significant asteroid, illustrating how even large space rocks can still take us by surprise. 2018 GE3 was found less than a day before before its closest approach.

Check out spaceweather.com.

They have a video up of what it looked like flying by at 0.5 LD from a guy's telescope in Austria!

That video is so cool!

a reply to: jadedANDcynical

Thank you for bringing this to our attention Jaded.

That actually sounds like the asteroid has similarities to the asteroid that caused meteor crater in Arizona (perhaps it was meteorite though!). I just remember reading the estimates on its size when I visited.

Nevertheless, that crater is a solid mile in diameter...Imagine if that had hit a major city like you mentioned. The casualties could have been in the millions even.

originally posted by: Puppylove
Wait... when was Tunguska confirmed to be an asteroid, and when did they suddenly have measurements?

I know it's been postulated that it was a meteor, but I didn't know it was confirmed to the point of being treated as fact... I thought Tunguska was a mystery to some degree.

It's only a mystery to those who want it to be a mystery.

We have witness reports, and the physical evidence that the event left behind (flattened forest), which are all consistent with the Tunguska event being an exceptionally large meteor which exploded in our atmosphere. Since then we have plenty of well documented events which show similar characteristics, albeit on a smaller scale.

We also know that there are plenty of objects that could cause such events orbiting our Sun (as this thread/story graphically demonstrates), and history shows that even larger events ("Meteor Crater" in Arizona, USA for example) occur from time to time, along with the relatively smaller fireballs which we see all the time.

Why would we not expect to see these mid-level events given all that?

The only real mystery of Tunguska, is we can not narrow down the source for sure. However there are some likely candidates, such as the Taurids which I wrote a post about some years back now. But just because we can't narrow down the source does not mean it was not a very large meteor. It could also have been a random asteroid, or unknown small comet/cometary fragment, like so many that bombard us all the time.

a reply to: jadedANDcynical

It would be great if one of these asteroids flys by earth close enough to hit low Earth Orbit and sweep away some of the space junk we have floating around up there.
Dangerous situation for us of course, but I'm talking about the perfect conditions that it just skims and sweeps the trash away.

originally posted by: DAVID64
a reply to: Puppylove

Just FYI, and all reading this, the above "front cover" image for the YT vid you posted is not an image from Chelyabinsk/Russia. In fact, it's not even an image of a fireball event!

It was actually a photograph taken by a Welsh schoolboy in 2003, and most agree that it was in fact a sunset-lit contrail.

originally posted by: Macenroe82
a reply to: jadedANDcynical

It would be great if one of these asteroids flys by earth close enough to hit low Earth Orbit and sweep away some of the space junk we have floating around up there.
Dangerous situation for us of course, but I'm talking about the perfect conditions that it just skims and sweeps the trash away.

Woudn't work. The distances between junk are huge, and even a massive object would just slip between them without disturbing them. Even something as large as the Moon might only mop up a tens of pieces of junk (and probably a few useful satellites too), and in order to do that the gravitational disruption to our Earth would be hugely disruptive/damaging to us I'd imagine. The risk is not worth it. Just let them come down on their own, as they will over time, relatively harmlessly. That's not to say junk isn't a problem, but why risk an even bigger problem?