Caught on video: small asteroid hits Earth with force of 500 Tons of TNT

A small asteroid hit Earth on Saturday, June 2nd, exploding in the atmosphere over Botswana before it could reach the ground. The Catalina Sky Survey in Arizona had discovered the space rock only hours earlier as it hurtled toward our planet from inside the orbit of the Moon. Sensors used to monitor rogue nuclear explosions detected the asteroid and estimated its yield near ~500 tons of TNT.

Artist’s concept of a near-Earth object. Image credit: NASA/JPL-Caltech

The Catalina Sky Survey in Arizona discovered a small asteroid (2018 LA) near the orbit of the Moon. Hours later, it hit Earth.

These are the discovery observations of asteroid 2018 LA from the Catalina Sky Survey, taken June 2, 2018. About eight hours after these images were taken, the asteroid entered Earth’s atmosphere (about 9:44 a.m. PDT, 12:44 p.m. EDT, 16:44 UTC, 6:44 p.m. local Botswana time), and disintegrated in the upper atmosphere near Botswana, Africa.

The boulder-sized space rock entered the atmosphere traveling 38,000 mph (17 km/s) and exploded over Botswana at 6:44 p.m. local time. A video camera at a farm near Ottosda, South Africa, recorded the explosion. It was impressively bright even at a distance:

The explosion sent waves of low-frequency sound (infrasound) rippling through the atmosphere, and it was detected by an infrasound monitor in South Africa, deployed as part of the International Monitoring System of the Comprehensive Nuclear-Test-Ban Treaty. Meteor expert Peter Brown of the University of Western Ontario analyzed the signals and came to these conclusions about the explosion:

“The yield was in the range 0.3 to 0.5 kilotons of TNT,” he says. “That corresponds to a 2 meter diameter asteroid.”

As asteroids go, that’s very small. It posed no significant danger to objects on the ground as it disintegrated almost wholly in the atmosphere. Fragments may yet be found on the ground and recovered for sale or scientific study.

The real significance of this event is that it highlights the growing capability of modern sky surveys to discover asteroids targeting Earth. Even small faint space rocks are being caught in the net. Boulder-sized impactors have been discovered hurtling toward Earth three times in the past 10 years: 2008 TC3 exploded over northern Sudan on Oct. 7, 2008; 2014 AA burned up above the Atlantic Ocean on Jan. 1, 2014; and now 2018 LA. In each case, the warning was less than a day. Larger asteroids may be seen at a greater distance, however, allowing for more lead time. Learn more about the latest impact from NASA.

Although there was not enough tracking data to make precise predictions ahead of time, a swath of possible locations was calculated stretching from Southern Africa, across the Indian Ocean, and onto New Guinea. Reports of a bright fireball above Botswana, Africa, early Saturday evening match up with the predicted trajectory for the asteroid. The asteroid entered Earth’s atmosphere at the high speed of 10 miles per second (38,000 mph, or 17 kilometers per second) at about 16:44 UTC (9:44 a.m. PDT, 12:44 p.m. EDT,6:44 p.m. local Botswana time) and disintegrated several miles above the surface, creating a bright fireball that lit up the evening sky.

When it was first detected, the asteroid was nearly as far away as the Moon’s orbit, although that was not initially known. The asteroid appeared as a streak in the series of time-exposure images taken by the Catalina telescope . As is the case for all asteroid-hunting projects, the data were quickly sent to the Minor Planet Center in Cambridge, Massachusetts, which calculated a preliminary trajectory indicating the possibility of an Earth impact. The data were in turn sent to the Center for Near-Earth Object Studies (CNEOS) at NASA’s Jet Propulsion Laboratory in Pasadena, California, where the automated Scout system also found a high probability that the asteroid was on an impact trajectory. Automated alerts were sent out to the community of asteroid observers to obtain further observations, and to the Planetary Defense Coordination Office at NASA Headquarters in Washington. However, since the asteroid was determined to be so small and therefore harmless, no further impact alerts were issued by NASA.

“This was a much smaller object than we are tasked to detect and warn about,” said Lindley Johnson, Planetary Defense Officer at NASA Headquarters. “However, this real-world event allows us to exercise our capabilities and gives some confidence our impact prediction models are adequate to respond to the potential impact of a larger object.”

The ATLAS asteroid survey obtained two additional observations hours before impact, which were used by Scout to confirm the impact would occur, and narrowed down the predicted location to southern Africa. Infrasound data collected just after the impact clearly detected the event from one of the listening stations deployed as part of the International Monitoring System of the Comprehensive Nuclear-Test-Ban Treaty. The signal is consistent with an atmospheric impact over Botswana.

“The discovery of asteroid 2018 LA is only the third time that an asteroid has been discovered to be on an impact trajectory, said Paul Chodas, manager of the Center for Near-Earth Object Studies (CNEOS) at JPL. “It is also only the second time that the high probability of an impact was predicted well ahead of the event itself.”

The first event of this kind was the impact of asteroid 2008 TC3, which lit up the predawn sky above Northern Sudan on October 7, 2008. That was a slightly larger asteroid (about 13 feet, or 4 meters in size), and it was discovered a full 19 hours before impact, allowing for a large number of follow-up observations and a very precise trajectory to be calculated. The second predicted impact event was for asteroid 2014 AA, which was discovered only a few hours before impact on Jan. 1, 2014, in the Atlantic Ocean, leaving too little time for follow-up observations. The Catalina Sky Survey has been responsible for discovering all three of these small asteroids on impact trajectories, and all on the watch of the same observer, Richard Kowalski.

NASA’s Planetary Defense Coordination Office is responsible for finding, tracking and characterizing potentially hazardous asteroids and comets coming near Earth, issuing warnings about possible impacts, and assisting coordination of U.S. government response planning, should there be an actual impact threat. JPL hosts the Center for Near-Earth Object Studies for NASA’s Near-Earth Object Observations Program, an element of the Planetary Defense Coordination Office within the agency’s Science Mission Directorate.

Sources: NASA Spaceweather.com and NASA JPL


For more information about NASA’s Planetary Defense Coordination Office, visit:

https://www.nasa.gov/planetarydefense

More information about asteroids and near-Earth objects can be found at:

https://cneos.jpl.nasa.gov

https://www.jpl.nasa.gov/asteroidwatch

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Bill Taylor
June 4, 2018 11:10 am

just an ole hillbilly here but if it exploded in the atmosphere it did NOT “hit the earth”.

Bill Taylor
Reply to  Anthony Watts
June 4, 2018 11:19 am

no desire to argue at all…..i am sorry daring to be accurate……

Bill Taylor
Reply to  Anthony Watts
June 4, 2018 11:26 am

ty, i appreciate your efforts of having accurate info here

Reply to  Anthony Watts
June 4, 2018 11:23 am

Considering that most large meteors explode before impacting the surface, there aren’t a lot of semantics to argue.

Leo Smith
Reply to  David Middleton
June 4, 2018 12:09 pm

Isn’t the definition of a meteor one that doesn’t hit the earth- then it becomes a meteorite?

Bill Taylor
Reply to  Leo Smith
June 4, 2018 12:14 pm

yes that was my point……when it comes to meteors and meteorites the atmosphere and earth are considered NOT that same thing.

Reply to  Leo Smith
June 4, 2018 12:39 pm

Meteor is the rock (meteoroid) falling through the atmosphere.

Meteorites are the bits of rock scattered on the Earth’s surface or buried in a crater after the meteor either explodes in the atmosphere (common) or hits the Earth’s surface intact (rare).

jorgekafkazar
Reply to  Leo Smith
June 4, 2018 1:07 pm

I recall an early paper titled “The Meteoritic Risk to Space Vehicles,” which would imply that meteorites can also be in space.

Reply to  Leo Smith
June 4, 2018 1:41 pm

Generically, meteorites are the bits of a meteoroid after they stop moving… Irrespective of where they stopped moving: Earth, Mars, the Moon, a spacecraft… Although I think a meteoroid might not stop after hitting a spacecraft.

Jones
Reply to  David Middleton
June 4, 2018 12:49 pm

If no-one had seen it then could it have been said to have really hit at all?

Bryan A
Reply to  Bill Taylor
June 4, 2018 12:15 pm

Technically one could argue that If they find meteorites sourced by it on the ground then it did hit the earth surface (soft landings)

Reply to  Bryan A
June 4, 2018 12:50 pm

It’s unlikely that the landings would have been soft.

Bryan A
Reply to  David Middleton
June 4, 2018 2:06 pm

Soft as opposed to crater forming. If the boulder fragmented sufficiently in the atmosphere then any impactor would probably not carry enough energy to excavate any surface material.
I would term this a soft landing instead of something like the Winslow impactor

hunter
Reply to  Bill Taylor
June 4, 2018 2:27 pm

The Tunguska event technically blew up in the atmosphere as well.
The atmosphere responded by destroying a forest from the shock wave and fire.
The atmosphere is an integral part of Earth.
They all strike the Earth.
https://en.m.wikipedia.org/wiki/Tunguska_event

Felix
Reply to  hunter
June 4, 2018 2:29 pm

If the Tunguska Event were indeed an airburst asteroid or comet, then bits of it probably hit the ground as well.

stock
Reply to  Felix
June 6, 2018 1:54 am

I believe that it created a lake, which is why it was hard to find.

ATheoK
Reply to  Bill Taylor
June 4, 2018 2:33 pm

The proper term is a bolide. i.e. a meteor that explodes in the atmosphere.

Only the pieces of the bolide that reach Earth can be called ‘meteorites’.

Reply to  ATheoK
June 4, 2018 3:50 pm

Yep.

Technically… the chunk of rock falling through the atmosphere (meteoritic object) is a comet, cometary fragment, asteroid or meteorroid, depending on size and composition.

The light streak in the sky is a meteor.

A bolide is is a meteorid, asteroid or comet exploding in the atmosphere.

And meteorites, of all sizes, are the chunks of meteoritic rock that are found in craters or on the surface of the Earth or any other planetary body.

Most meteoritic objects explode prior to impact, hence bolides.

Red94ViperRT10
Reply to  David Middleton
June 5, 2018 12:07 pm

This is where I’m puzzled… what causes them to explode? Ice within the object that flashes to steam? Other materials reaching vaporization temperature? Or just the physical fact of that much kinetic energy converting to an equal amount of heat energy in such a short time frame? Somebody explain this to me!

stock
Reply to  Red94ViperRT10
June 6, 2018 1:56 am

MSME here, built calculators on this stuff…yes kinetic energy going bat shit crazy. Russia taught me, lol

June 4, 2018 11:19 am

Interesting video.

Klem
Reply to  Tom Halla
June 5, 2018 3:45 am

Interesting to me too. I can’t help but wonder why a farm in S Africa would require security cameras.

2hotel9
Reply to  Klem
June 5, 2018 5:37 am

Have you not been following news out of that region of late?

Latitude
June 4, 2018 11:21 am

“, a swath of possible locations was calculated stretching from Southern Africa, across the Indian Ocean, and onto New Guinea. Reports of a bright fireball above Botswana, Africa, early Saturday evening match up with the predicted trajectory for the asteroid.”

LOL….ok that made me laugh

Sounds like the NHC claiming they predicted it….when they have the cone of death from Maine to Rio….and then change it every 5 mins

Writing Observer
Reply to  Latitude
June 4, 2018 12:50 pm

Well, the article is not well written – they contradict the earlier sentence later on, where they said that more observations narrowed it down to just Southern Africa.

Note, again, that Anthony did NOT write the article.

RAH
Reply to  Latitude
June 4, 2018 5:21 pm

I’m just glad they detected it. Shows progress in seeing NEOs.

Klem
Reply to  RAH
June 5, 2018 3:38 am

Just think how much better their predictions might be had we directed a bit more funding their way, rather than toward fighting the invisible devil CO2.

dave
June 4, 2018 11:31 am

It hit “the Earth” but not earth.

Felix
Reply to  dave
June 4, 2018 11:40 am

It was said that Comet Shoemaker-Levy 9 hit Jupiter, but surely its chunks didn’t reach the solid surface of that gas giant planet.

IMO, its atmosphere is part of a planet, but not its magnetosphere.

Bob boder
Reply to  Felix
June 4, 2018 12:38 pm

Is there a solid center?

Ed Zuiderwijk
Reply to  Bob boder
June 4, 2018 1:25 pm

A rocky core and a mantle of metallic hydrogen under extreme pressure. Needed to explain the strong magnetic field of the planet.

Felix
Reply to  Bob boder
June 4, 2018 1:58 pm

Probably. Fourteen years old, but still relevant:

Shock Compression of Deuterium and the Interiors of Jupiter and Saturn

http://iopscience.iop.org/article/10.1086/421257/meta

Abstract

Recently, deuterium has been the focus of a high level of experimental and theoretical activity, sparked by a disagreement on the experimental value of the maximum compression along the principal Hugoniot. The behavior of deuterium at megabar pressures is not well understood. It is of great interest to understand how the current uncertainty on the hydrogen/deuterium equation of state (EOS) affects the inferred structures of Jupiter and Saturn. In particular, the mass of a core of heavy elements (other than H and He) and the total mass of those heavy elements in these two planets are quite sensitive to the EOS of hydrogen and constitute important clues to their formation process. We present a study of the range of structures allowed for Jupiter and Saturn by the current uncertainty in the hydrogen EOS and astrophysical observations of the two planets. An improved experimental understanding of hydrogen at megabar pressures and better determinations of the gravitational moments of both planets are necessary to put tight bounds on their internal structure.

June 4, 2018 11:37 am

I make a distinction between the phrases, “hitting the Earth” and “hitting the Earth’s Atmosphere“, and I dare say that most people do the same. “Hitting the Earth” is, of course, far more dramatic, and I bet NASA chose this manner of writing to be dramatic and scary looking. After all, being scared about Earth’s being destroyed is apparently fun.

HEADLINE: Carbon Dioxide Molecule Is Destroying The Earth

Steinar Midtskogen
June 4, 2018 11:41 am

If the entry speed was as low as 17 km/s, there is a good chance that the explosion also dropped many meteorites, possibly several 100 kgs in all.

Lance
June 4, 2018 11:46 am

In the mid 80’s I was doing a lot of ‘telescope’ work as a hobby. Myself and several members of our Ft. Mac group would drive Peter Brown out to dark skies, and he would setup and track all the meteors! It was great to see he took this to the next steps!

Will Nelson
June 4, 2018 11:56 am

It did not “hit” the earth… nor did it miss the earth. Luckily I had that copy of ‘War and Peace’ in my pocket.

ossqss
June 4, 2018 12:01 pm

Kinda makes one feel a bit vulnerable. Sure wish we could get some type of warning ahead of time and not an epilogue 🙂

Javert Chip
Reply to  ossqss
June 4, 2018 12:18 pm

Exactly what would you do if (knowingly) threatened by a meteorite traveling in excess of 38,000MPH? Put up your umbrella?

jorgekafkazar
Reply to  Javert Chip
June 4, 2018 1:10 pm

Jumping into your fallout shelter is highly recommended, if you have one.

Mr Bliss
Reply to  jorgekafkazar
June 4, 2018 5:06 pm

My council told me to take down my fallout shelter – they said I needed planning permission to put it on the roof of my block of flats

ossqss
Reply to  Javert Chip
June 4, 2018 1:30 pm

LOL, quite a bit if I had an hour or so! 🙂

Reply to  Javert Chip
June 4, 2018 1:50 pm

At the very least, if it looked like a threat to people, we could shoot a missile at it. The chance of a hit is > 0.

Reply to  Bob Shapiro
June 4, 2018 5:35 pm

Unless… hitting it with a missile makes it worse.

Wallaby Geoff
Reply to  ossqss
June 4, 2018 2:11 pm

There are many things to worry about being hit by – ahead of a meteorite. If I started a list, it would be the last item. Motor vehicle would be #1.

Felix
Reply to  Wallaby Geoff
June 4, 2018 2:19 pm

While the probability is low, being hit by a killer asteroid or comet carries the risk of mass death and destruction.

Reply to  Felix
June 4, 2018 3:53 pm

Al Gore says motor vehicles are worse… 🤣

MarkW
Reply to  David Middleton
June 4, 2018 4:50 pm

Except, apparently, when those motor vehicles are carrying him.

Felix
Reply to  David Middleton
June 4, 2018 5:00 pm

I don’t see Prince Albert giving up fossil-fueled air, sea or land travel, nor heating and cooling his many residences, including that by the Pacific Ocean. Nor selling his oil company stock shares, ill gotten by his dad from Communist agent Armand Hammer.

J Mac
June 4, 2018 12:06 pm

It was discovered a few hours before entering Earth’s atmosphere and exploding. That is not at all reassuring.

Leo Smith
Reply to  J Mac
June 4, 2018 12:14 pm

But it was a tiddler.

Anyway comfort yourself with…

“And its one two three four
What are we fighting for?
Don’t ask me I don’t give a damn
Next stop is Vietnam
And its five six seven eight!
Open up them pearly gates.
Ain’t no time to wonder why…
Whoopee! we’re all gonna die!”

Reply to  Leo Smith
June 4, 2018 3:56 pm

+++ Gotta love Country Joe & the Fish

J Mac
Reply to  Leo Smith
June 4, 2018 4:05 pm

That song by Country Joe and the Fish was dumb in the 1960s….and it has not improved with age. Comfort yourself, by at least providing the correct lyrics next time.

Felix
Reply to  J Mac
June 4, 2018 6:50 pm

Country Joe McDonald’s Russian Jewish mom and Scots Presbyterian dad were Commies who named their misbegotten spawn for Joseph Stalin. At least he did a stint in the US Navy before becoming a busker on the streets of SF.

Barry “The Fish” Melton’s mom was the daughter of Communist Jewish immigrants from Odessa, and his dad’s family were of Texas pioneer descent, but radicals. Like so many other Commies, he was attracted to folk music, while not participating in Commie front groups like CORE.

Leo Smith
Reply to  Felix
June 4, 2018 11:46 pm

Sure, but it was still an amusing rag.

Felix
Reply to  J Mac
June 4, 2018 6:55 pm

PS: The Fish is a former public defender in Yolo County, not far from our esteemed host’s AO.

tty
Reply to  J Mac
June 4, 2018 12:14 pm

I think finding a two-meter object 300,000 kilometers out is pretty good.

Reply to  tty
June 4, 2018 3:57 pm

Yep… Gotta find’em before we can even begin to figure out if we can shoot’em.

HotScot
Reply to  J Mac
June 4, 2018 12:36 pm

J Mac

It would be very reassuring had we the ability to defend against it. Sadly, we could see one coming a week before, still nothing we can do about it.

Makes me wonder if the global space agencies would even bother warning us if there was a big one a week away.

I suppose if they did we could enjoy a last beer without worrying about our health.

jorgekafkazar
Reply to  HotScot
June 4, 2018 1:14 pm

We’d have a right to know, and failure to warn would create a huge liability claim. IIRR, some Italian seismologists got blamed for loss of life during a quake that others thought they should have predicted. Acme Torch & Pitchfork Co. would make a lot of money the day after an impact.

HotScot
Reply to  jorgekafkazar
June 4, 2018 1:23 pm

jorgekafkazar

My concept of “a big one a week away” means there would be no insurance companies, lawyers, or victims left.

Hence, having a last beer (and a cigarette, which I gave up decades ago) without having to worry about the health consequences.

🙂

MarkW
Reply to  jorgekafkazar
June 4, 2018 2:46 pm

The Italian seismologists made positive statements in the press that there was no earthquake imminent.

markl
Reply to  HotScot
June 4, 2018 1:36 pm

“… we could enjoy a last beer without worrying about our health….” Isn’t that every beer?

Reply to  HotScot
June 4, 2018 4:00 pm

I’ve got 2 bottles of Caymus and 2 of Stags Leap cab in the “wine cellar”… I want to spend my last few hours doing something productive… 😎

Reply to  HotScot
June 4, 2018 6:40 pm

If headed to Washington DC, They would have enough time to evacuate the White House, Congress, ….

ahhh heck, on second thought, don’t tell Congress.

Reply to  J Mac
June 4, 2018 1:22 pm

I genuinely disagree: That the pan-sky survey(s) can find an object the size of 2 meters in diameter … at the distance of the Moon … and whizzing on a course destined for atmospheric disintegration only hours before the event happens — is absolutely amazing. There is a LOT of sky to look at. Even if one’s wide-field telescope (per/ea) has a sensor field of 3° x 3°, there still is a LOT of images to take.

Let’s say “48 × 36 mm plates”, and moreover an array of 2 × 3 of them (6 total) in the focal plane of a Schmidt Cassegrain or other widely-regarded ultra-wide capable telescope. We’ve got a 24 inch primary (say), and the optics is done in the visual wavelengths (around 550 nm). The telescope is diffraction-limit ground, and yet we won’t have enough pixels to accommodate the theoretic resolution. No matter… air turbulence will whack the image plane enough that 10 μm pixels are good enough.

There are still 95,000,000 pixels in the 6° x 6° field of the 6 plates. And, at an albedo of 0.25 (kind of darkish), at Moon (400,000 km), the 24 inch telescope would be detecting some 300 photons per second from the wee asteroidal disk. Not small! Yet, even so, there are 572 of the 6° x 6° “plates worth” to cover the whole hemisphere of the dark night sky.

Not being space-based, there being the airglow of horizon cities and metropolises, perhaps only 300 plates cover the available sky at any moment. Once every 5 seconds, reposition the robotic telescope, take another snap; maybe keep the aperture open for most of that. 300 × 5 seconds is 1,500 seconds to make ONE pass over the night sky. 1500 ÷ 60 = 25 minutes a pass. You’ve got maybe 8 observation ‘clean’ hours a night (less in Summer, more in Winter). 8 × 3600 ÷ 1500 ≈ 5 to 10 whole-sky passes per evening.

If you really need longer exposure times, we got to buy more telescopes, or telescopes with larger apertures, or the equivalent.

As I said… amazing stuff.
Great science.

GoatGuy

Latitude
Reply to  GoatGuy
June 4, 2018 1:51 pm

I’m leaning in the direction of a luck shot…..there’s been many of them recently they didn’t catch

Reply to  GoatGuy
June 4, 2018 2:24 pm

“572 of the 6° x 6° “plates worth” to cover the whole hemisphere of the dark night sky.”

But even a PC or laptop will be able to determine “what’s changed” for that many images in just a minute or so. This searching has mostly been automated since ultra-sensitive giga-pixel CCD arrays have largely replaced photographic film plates. I suspect the detection rate and detection thresholds will continue to improve.

Reply to  co2isnotevil
June 4, 2018 3:07 pm

I suspect the detection rate and detection thresholds will continue to improve.

Maybe, except for the fact that physics steps in the way for detection a whole lot of the time. Consider this thought exercise:

You have a light bulb – rather powerful one – maybe 1,000 watts of output of brilliant white light. Its sitting on satellite, otherwise black, so that the light is the only meaningful emission from the satellite. The satellite is beyond the Moon, or say 1,000,000 km away.

You also have a “detector” — a nice custom built 24 inch (diameter)telescope say sitting in the middle of Argentina’s Atacama desert with nearly perfect seeing conditions. How many photons from that brilliant light — 1,000,000 km away — are going to be received by the excellent 24 inch telescope, if the satellite happens to pass overhead in front of the telescope’s waiting aperature?

Turns out that straight physics can answer all these questions in a jiffy. That distance (1,000,000 km) means that the output wattage of the light (1,000 W), uniformly distributed over a hemisphere pointing more or less our direction is going to deliver some 128 photons per second (perfect atmosphere, etc.) to the telescope. And real-world detectors might capture 65% of those, for an 83 photon/sec detection rate. The limits of the detector can only get efficiency closer and closer to 100%, never achieving it, or over 100%.

Also straight physics limits the size of the imaging array sitting at the focal plane of the telescope. Real-world telescopes have all sorts of reducible, but not irreducible aberations that prevent good focus outside the very center of the focal plane made by the primary mirror. So-called “correctors” do a great job increasing the distance-from-center that crispy clear images can be realized.

But, in so doing, its always “borrowing from Peter to pay Paul”.

If you get a clear image 2× further from center with a complex correction plate system, the image outside that sweet circle will be doubly or triply (or worse) smeared. That’s how optics work.

So the idea of adding more and more sensors to the focal plane to increase the coverage ‘per shot’ is a good idea, but is vexed with real-world physics. Making a mirror with higher focal-length-to-aperture ratios (“magnifying the field of view”) doesn’t fix the problem. You see fewer square degrees, albeit sharper. You can cover the field with more sensors, but again in terms of DEGREES of sensor plate acceptable optics, its nearly a wash.

So as I concluded above, the only real solution in the end is

• More telescopes
• Larger telescopes
• More observatory locations

Where the ultimate solution would be

• Space based,

With hundreds of scopes, all pointing a hundred different directions, slewing the entire view of the heavens every day, 100× a day, continuously.

Slightly more (by a factor of well over 1,000) of what a “laptop or desktop” can autocorrelate.
Just saying,

GoatGuy

Reply to  GoatGuy
June 4, 2018 6:47 pm

We can detect them at or near opposition, as they approach our orbital position.

But NEO asteroids can approach Earth from conjunction and there is zero hope of seeing it approach from that direction.

MarkW
Reply to  J Mac
June 4, 2018 2:44 pm

The smaller the rock is, the harder it is too spot.
Regardless, there are quite probably, a large number of rocks big enough to do damage that haven’t been spotted yet.

John Harmsworth
June 4, 2018 12:11 pm

If we really wanted to know something about “global warming” we would have satellites up there that can determine IR increase after an impact. Then we could check that against the altitude and magnitude of the explosion to find out how much our CO2 delays the heat loss.
Anything wrong with that idea? Cost is not a valid answer as we are spending billions on the official fairytale.already.

Leo Smith
Reply to  John Harmsworth
June 4, 2018 12:16 pm

If we really wanted to know if renewable energy was working we would have sodding big dials showing how much CO2 were were (not) emitting.

But that data is almost impossible to find….

tty
June 4, 2018 12:17 pm

“Anything wrong with that idea? ”

Yes. A small asteroid explodes high in the atmosphere above most of the CO2, and the temperature is extremely high, so high in fact that a lot of the energy comes out as visible light, not infrared. It is completely irrelevant to “global warming”.

Bill Illis
Reply to  tty
June 4, 2018 7:00 pm

One of the issues is just how high can these EM emissions get from a really large, really fast asteroid.

I think a large asteroid would effectively blind you in a second and then it would probably fry you alive and everything within sight of it just from the high energy EM emissions.

Felix
Reply to  tty
June 4, 2018 7:09 pm

Brighter than a thousand suns.

But the real killer would be the higher-energy UV light, X-rays and gamma rays.

tty
Reply to  tty
June 6, 2018 1:55 pm

UV, yes, but no reasonable temperature will output x-rays. Even soft x-rays requires temperatures on the order of 10^6 K.

Felix
Reply to  tty
June 6, 2018 2:06 pm

I was thinking of K/T-sized and larger asteroids, but you’re still right.

JP
June 4, 2018 12:23 pm

Just the other day, I was reading about a sudden but rapid plunge in global temperatures beginning in 536AD and continuing for the next decade. The plunge in temperatures was accompanied by a canopy of dust high up in the atmosphere. Byzantine historians recorded a “shrouded sun and moon’. Norsemen living in Scandinavia reported snows in June and July; The Vandals in North Africa and Southwest Europe reported frigid summers, and terribly cold and snowy winters. Famine and starvation occurred in Asia and South America. Some anthropologists believe half the global population died off during this 10 year period.

Some blame volcanoes. But, this event lasted a decade. Geologists detected a thin layer of different elements in ice cores for this period. The deduced that several meteors had air burst into the atmosphere from Indonesia to the Indian ocean, and that debris from this event was thick enough to remain suspended high up in the atmosphere for several years.

Sara
June 4, 2018 12:34 pm

Well, that’s a twofer. I know, I know: we get meteors impacting all the time, mostly where no one pays any attention them.

First it was the Chelyabinsk bolide, then that bright one over Finland, now it’s this one. And it isn’t even big enough to warrant a rider for my HO policy for ‘impact by and damage cause by extraterrestrial objects’.

This one had a nice whoosh + splodey-rock effect. But there are more out there. I keep hoping that one of them will do a smackdown on some truly unimportant event like a gathering of — oh, never mind. I can dream, can’t I?

jorgekafkazar
Reply to  Sara
June 4, 2018 1:19 pm

There are certain events and people I’d avoid, just to be on the safe side. Lightning is also a possibility in some cases.

haverwilde
June 4, 2018 12:40 pm

Too many pedants can ruin a great story.

😉

The video is awesome.

Leo Smith
Reply to  haverwilde
June 4, 2018 11:52 pm

If you want the ultimate exercise in metaphysical pedantry Google the issue of “Theseus’ ship”

And then consider how many of humanities problems are caused by our inability to separate reality from our [verbal] description of it?

Is he the Messiah? No, he’s a very naughty boy…

Jeff Alberts
Reply to  Leo Smith
June 5, 2018 6:03 pm

Alright I AM the Messiah! Now F*** OFF!

bw
June 4, 2018 12:43 pm

Using a converter for 400 tons TNT to Joules shows about 1700E9 Joules which is 1700 GJ (gigajoules).
Assuming the energy released during the event is entirely due to kinetic energy, then at 17000 meters per second, using 1/2 mv squared, gives a mass of about 12000 kilograms, that’s 12 tonnes.
12 tonnes of rock at an average density of 2.5 kg per cubic meter is a volume of 4.8 cubic meters. Which is close to the volume of a sphere of 1 meter radius.

Guessing a track of 5000 meters, the volume of a cylinder of 1E9 cubic meters will have a radius of 250 meters. The mass of the atmosphere in that volume will be about 1E9 kilograms.
Then 1700E9 joules is absorbed by 1E9 kilograms of mass. The specific heat of air is 1kJ/kg per degree, so the air in the cylinder will increase by 1700 degrees C
Not surprising that 12 tonnes of rock becomes ionized gas in a few seconds

Scarface
Reply to  bw
June 4, 2018 1:03 pm

Wow!

bw
Reply to  bw
June 4, 2018 1:20 pm

The last calc is off. 1700E9 joules should be 1.7E9 kilojoules. So the temperature increases by 1.7 degrees. Obviously the volume of the event is much smaller than the first guess, by at least a factor of several thousands. Also, the heat transfer of the hot rock is not conductive, but mostly radiative. The air does not absorb much light in the visible spectrum, so most of the heat transfer from rock to air must be in the infrared. And most of that in a radius of maybe 10 meters along the path of the event.
A video using infrared cameras might have been spectacular.

Clyde Spencer
Reply to  bw
June 4, 2018 2:10 pm

bw,
Your estimate of the density is also probably on the low side. Even if it had little or no iron in it, the density was probably closer to about 3.2.

Reply to  bw
June 4, 2018 3:28 pm

The last calculation wasn’t THAT far off, actually.

400 mT = 0.4 kT
1 kT = 4.186×10¹² J (look up)
∴ 0.4 kT × 4.186×10¹² J → 1.674×10¹² J.

Pretty close to 1700×10⁹ J.
A couple of percent.

GoatGuy

tty
Reply to  bw
June 6, 2018 2:01 pm

“A video using infrared cameras might have been spectacular”

Doubtful. Except for the “Window” the atmosphere is pretty much opaque to IR. In any case a bolide is so hot that most of the energy output is visible light or UV.

bwegher
Reply to  tty
June 6, 2018 2:34 pm

IR cameras have been around for decades
https://en.wikipedia.org/wiki/Forward-looking_infrared

June 4, 2018 1:00 pm

While watching the Persiad meteor shower back in 2007, I witnessed a small bolide pass overhead and explode about 1/4 mile from where I was camping deep in the Sierras, North of Yosemite. It was quite impressive, almost Armageddon like. The next year, I went to where I saw it fall, did a grid search and found what seems to be several kg of carbonaceous Chondrites including some relatively big pieces. It’s on the dense side of most of this type, pitch black with small white inclusions, the biggest piece has clear glassification, exhibits the musty odor of other samples, contains amino acids and has significant water in the matrix itself. Pretty cool stuff …

https://www.amsmeteors.org/members/imo_view/event/2007/274

jorgekafkazar
Reply to  co2isnotevil
June 4, 2018 1:22 pm

Well done. Those are the “Perseids,” by the way.

Reply to  jorgekafkazar
June 4, 2018 1:59 pm

I’ve always wondered if I have pieces of the Swift-Tuttle comet. If it could be verified, I suspect a kg+ piece of this comet could be worth something, especially the piece with glassification which has the shape of a wing and which almost appears to have been oriented to it’s trajectory through the atmosphere.

Felix
Reply to  co2isnotevil
June 4, 2018 2:27 pm

Yup. All the building blocks of life arrived on Earth from outer space, if not full-fledged microbes themselves.

Doesn’t mean that amino, nucleic and fatty acids didn’t also develop spontaneously on the early Earth as well, where conditions were ideal for their self-assembly.

These constituent components of biological molecules naturally polymerize in the liquid water between ice crystals, so proteins, long nucleic acid chains and spherical lipid membranes could have developed on asteroids, on Earth or both.

hunter
Reply to  co2isnotevil
June 4, 2018 4:33 pm

Awesome! Good sleuthing. Best wishes getting it valued.

Michael Kelly
June 4, 2018 4:23 pm

When I told her the meteor had a yield of 500 tons, she reminded me that the camera adds 10 tons…

Peter Sable
June 4, 2018 5:31 pm

Luckily it is such a remote region that there’s no official thermometers for thousands of kilometers, so none of those rare items got damaged. Thank goodness the interpolation of temperatures in that region was unaffected.

dodgy geezer
June 4, 2018 9:21 pm

….The Catalina Sky Survey has been responsible for discovering all three of these small asteroids on impact trajectories, and all on the watch of the same observer, Richard Kowalski…

He must be causing them! After all, it’s correlated, and we can’t think of anything else it could be…

Why not try taking him off watch and see if that stops the impacts? That would be a good study…Oh, and I nearly forgot – send me money …

June 5, 2018 2:17 am

Easy to spot and track it since it was moving against the background of stars. Now suppose it was coming in from a location where its collision course had a constant bearing, and rapidly decreasing range.

This one was about 2 m diameter and was spotted near the Moon. How big would it have had to have been if on constant bearing at that range and therefore not moving against the stellar background? All that would have been detected would have been a gradually increasing source of light, but same location with respect to the nearby stars. Easy to confuse with a nova, perhaps?

bonbon
June 5, 2018 4:02 am

Ironically the largest impact site, in Austrialia from 540million years starting the Cambrian biosphere explosion, went unnoticed because of the sheer scale – 650km diameter. No idea how many Megatons equivalent. Things can get shaken up passing through those galactic spiral arms….

ozspeaksup
June 5, 2018 4:53 am

it was shown on spaceweather.com as having a ZERO distance from earth..I did wonder at the time i saw it….that it meant impact was probable

2hotel9
June 5, 2018 5:41 am

Now this is science! And actually useful, to some degree. Like telling the pitcher he is going to get smacked by the ball 1/1000th of a second before it happens. Objects detected that close in are moving sort of fast, not much lead time for warnings.

Tom Schaefer
June 5, 2018 6:52 am

So the gist of it is that if you want rocky meteor, you need to go get it. You can’t just hope to drive out and get some from a crater. I LOVE the nickel-iron meteors on display in the Smithsonian’s Rocks and Minerals hall, and have for over 50 years now, as do my children. I am cheering for DeepSpaceIndustries.com and PlanetaryResources.com ! I can’t wait until they go public.

Olen
June 5, 2018 7:18 am

Fortunately it did not explode over an international airport.

tty
Reply to  Olen
June 6, 2018 2:11 pm

As a matter of fact the impact was near Gaborone which has an international airport.

J.H.
June 6, 2018 2:03 am

Yet they missed spotting and tracking that big Meteor over Chelyabinsk in Russia, 2013….

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