The Great Daylight Fireball

I came across this the other day while searching some information about sky noises and fireballs. This was a fireball that appeared over the Rocky Mountains back on August 10, 1972 at about 2:30 pm that was so bright it was visible during the day time. The most interesting part is that they call this an “Earth-grazer” which means it didn’t actually have impact. It came just inside of our atmosphere and skipped back out to space. It was estimated to be about 20 meters in size, so if it had actually had impact or an airburst (the Tunguska event) it would have been devastating. If this meteor had only been off by a few miles it may have had such a devastating effect that life here in America wouldn’t be as we know it today. In astronomical terms, a few miles is like a hair. So, if this Great Daylight Fireball of 1972 had been off by a hair (literally) we would have had a Tunguska event right over Utah, Idaho, or Montana.

Tunguska Event

It really makes you think how ‘not in control’ we really are in the overall scheme of things. This picture was taken as the fireball traversed across the sky beyond the Grand Teton Mountains. It was taken in Jackson Hole, WY looking to the west.



This Great Daylight Fireball of 1972 bounced off Earth’s atmosphere much like a stone skips on a pond. This event was witnessed by thousands of people, caught on two films and several photos, like the one above. Later it was discovered that an Air Force satellite had also tracked the meteor as it passed. That’s how it is known that the meteor was in our atmosphere for 101 seconds as it entered over Utah just southwest of Salt Lake City, traveled north and exited over Alberta, CN.




This Earth-grazer was said to be traveling about 33,000 mph and at its closest point to Earth it was about 35 miles above. It was said to be about the size of a small truck. These Earth-grazers are rare but are more commonly seen when the radiant of a meteor shower is rising or setting. This meteor shower was part of the Apollo asteroid class and was in an Earth-crossing orbit in August of 1972. The same class was expected to cross paths with Earth again in August of 1997. Many people watched and waited to see if the same meteor would approach again. A Czech astronomer named Zdenek Ceplecha had analyzed the data about it approaching again and suggested that the passage through Earth’s atmosphere in 1972 would have reduced its mass to about a third or half of its original mass reducing its diameter to anywhere from 2 meters to 10 meters. The passage also reduced its velocity by about 800 meters per second to about 2,600 feet per second and the whole encounter significantly changed its orbital inclination from 15 degrees to 8 degrees.

Short video of fireball

You can search YouTube for other video's. Also, on video above you'll find some witness accounts.

This fireball was quite impressive and it makes you wonder when to expect our next visit from an ‘Earth-grazer.’ Somewhere out in the dark depths of space lurks that next meteor, asteroid or comet with our name on it.

The following are some witness recollections of the Great Daylight Fireball of 1972 from Jess Mullins website.

Great Daylight Fireball

I witnessed what has been called the nearest approach of an asteroid ever observed. It is now known as “the Great Daylight Fireball of 1972,” and the details of its flight across the sky are well documented. On that warm summer day I was walking with another cowboy from the bunkhouse toward the employee’s dining room at the main ranchhouse, where lunch awaited us. The path we were taking—south and slightly westward—caused us to be facing the object as it came into view. Just to give some perspective—our line of view was across Jackson Hole, with the Grand Tetons lying off to the west (our right). One report estimated the object’s “entry mass” at 4,000 metric tons, and its diameter at about 20 meters. For us, it was mostly approaching, though at an angle to us. We could see the face of the rock. It did not look like something real. It looked instead like a bad display of special effects, like something out of an old Flash Gordon movie. Flames were erupting across the face of the rock, stripping away, re-erupting.

Here's more of his account

We guessed at the time that it went down in the Teton Wilderness that was to our backs— we knew there was more than a hundred square miles of it. Then later we heard the thing was sighted over Montana. But the most amazing part is that the bolide never touched earth at all. Apparently it entered the atmosphere and exited back into space somewhere over Canada, continuing on its way through the void. Until recent years I have disbelieved the reports that the object passed over Utah, not Wyoming, and that it was roughly 35 miles or more above the surface of the earth. It seemed to my companion and I that it was low – hardly higher than a jetliner would fly – and that it was within cloud level. As I said, we thought it would have struck the earth north of us, somewhere well short of Montana. And at the time we had to look at it for some seconds to be sure that it was not a plane on fire. So, obviously, we did not think it was an object passing over a neighboring state. Also, in one of the videos that can be viewed on YouTube, the meteor seems to be piercing a cloud that hangs just above Jackson Hole. It seems to shred a part of the cloud as it “exits” it.

Read more of his page at the website and you'll get some more witness accounts. One more witness account.

I grew up around Air Force bases and I’ve heard sonic booms many times. But nothing as deep and as resounding as this one. In an instant the fish ran back under the bridge. He was permanently spooked. I’d never see him again. The great hunk of rock, glowing and hissing and trailing smoke, passed directly over my head, from south to north, and sailed out of sight behind Mount Jumbo. Gaping at the place where it had gone I wondered: What just happened here? Am I hallucinating? Was this an illusion, some kicking-in of a random bit of mescaline or '___' that had lodged in a remote back alley of my brain? But as I would learn, the thing I had seen was real. Thousands of people from Utah to Canada had witnessed what would be called The Great Daylight Fireball of 1972. There were hundreds of pictures taken of the thing, and a pair of home movies, and it was tracked using infrared sensors aboard an Air Force satellite. Scientists inferring from the temperature of the ball and its 900-mile trajectory from Utah to Alberta calculated that it passed over Montana at an altitude of less than 35 miles, was between ten and thirty feet in diameter, and weighed at least 4,000 tons, big enough to obliterate a Denver-sized city with a force equal to Little Boy and Fat Man, the uranium and plutonium bombs that destroyed Hiroshima and Nagasaki. Because no trace of the beast has ever been found, and because no sonic booms were heard as it sailed across Canada, astrophysicists now believe its low angle of descent allowed it to skip off the earth’s atmosphere like a flat stone on a still lake. One scientist predicted that the fireball would return in 1997, but no one saw it. In 1972 the earth dodged a bullet. My fish dodged a bullet. And I dodged two bullets. From then on just standing by a stream would always seem a little bit like winning a prize.

Santini?

reply to post by Aleister


Lol, mistakenly hit enter or something before I was able to make the post, but here it is now.

reply to post by Rezlooper

Nice history. I'm surprised that a few people were quick enough in those days to get a picture (focus, aim, click, wait for the picture to develop).

One thing to note about this fireball was how slow it was moving for a meteor. Average speeds of meteors are 10 to 70 km per second while this one moved about 14 km per second. Pretty slow for a meteor. If you watch that short video you can see witnesses were able to watch it move slowly across the sky. Another interesting part of the video is that at first, many witnesses thought it was at cloud level, as you can see early in vid it appears to come exiting out of the cloud.

Great post
That video is amazing, wish i could see something similar in my lifetime

Good thread Rezlooper I always enjoy discussing meteors, especially earth grazers. The Great fireball of 1972 is a classic example of a big grazer!

Originally posted by Rezlooper
This fireball was quite impressive and it makes you wonder when to expect our next visit from an ‘Earth-grazer.’ Somewhere out in the dark depths of space lurks that next meteor, asteroid or comet with our name on it.

We've already had two major earth-grazing fireballs this year. Quite a coincidence, but both occurred over the UK.


The first was in early March, and was witnessed by hundreds of people:
NEW!!: Mystery Meteor Flashes Across British Skies

The second was in late September, and was also witnessed by many people:
Meteor Over the United Kingdom

The September grazer turned out to be a rather special event which researchers are still pouring over:

What was unusual about it (as if earth-grazing fireballs aren't unusual enough!) is that it may have been temporarily captured by Earth;s gravity (ie. in orbit around Earth), which is something that is not often observed, and has never been captured on camera before.

ATS: Call for video/photographs of September 21, 2012 fireball

Whilst big earth grazing fireballs are quite rare, smaller earth grazing meteors (and occasionally fireballs) are not that hard to see if you are prepared to be patient, and spend time observing annual meteor showers, especially when the radiant is low (as you mentioned in your OP).

In fact, there are a couple of possible opportunities for people to observe earth grazers for themselves coming up in the next few days. See my thread here: Major meteor showers predicted in the next month

I have been very fortunate in the past to have observed a few dozen earth grazing meteors and fireballs, mostly during the build up to the Leonid meteor storm of 2001, when I also managed to photograph a few, including this rare all green (I've never come across a photograph like it) Leonid earth grazer:

reply to post by FireballStorm


Thanks for the added info, two more Earth-grazers this year alone. Whoa. I'll be doing some skywatching over the next few days with this new meteor shower. Maybe I'll get to see one of these in my lifetime as well.

reply to post by FireballStorm


And how were you so fortunate enough to catch that photo?

Originally posted by Rezlooper
One thing to note about this fireball was how slow it was moving for a meteor. Average speeds of meteors are 10 to 70 km per second while this one moved about 14 km per second. Pretty slow for a meteor. If you watch that short video you can see witnesses were able to watch it move slowly across the sky. Another interesting part of the video is that at first, many witnesses thought it was at cloud level, as you can see early in vid it appears to come exiting out of the cloud.

I doubt your 'facts'
Maybe you should check out This for speed of meteors
It seems earth approaching objects don't read your posts.

wow, that was close...
if i had been living where i do now then,
i would have been lucky enough to see it
in person. Back in that year though i was
living in texas.
the photo looks like a lake that is close to here.

Talk about some close calls,
Think i'd need to change my undies if i had seen it
though.

Originally posted by cody599

Originally posted by Rezlooper
One thing to note about this fireball was how slow it was moving for a meteor. Average speeds of meteors are 10 to 70 km per second while this one moved about 14 km per second. Pretty slow for a meteor. If you watch that short video you can see witnesses were able to watch it move slowly across the sky. Another interesting part of the video is that at first, many witnesses thought it was at cloud level, as you can see early in vid it appears to come exiting out of the cloud.

I doubt your 'facts'
Maybe you should check out This for speed of meteors
It seems earth approaching objects don't read your posts.

edit on 30-12-2012 by cody599 because: (no reason given)

I don't know much about that site you reference but from what I've heard on ATS here from other posters in other threads is that they don't trust that site or give it much credit.

From Yahoo Answers

Depends on its direction. Meteors entering our atmosphere from the east are moving faster than ones entering from the west (since the Earth is rotating towards the east, a meteor entering from that direction has the Earth's rotational speed added to its own motion). The slowest meteor shower is the June Bootids, where they average around 14 km/sec. The fastest meteor shower is Leonids, with an average speed of about 70 km/sec.

And this one

The average velocity of meteoroids entering our atmosphere is 10-70 km/second. The smaller ones that survive the trip to the Earth's surface are quickly slowed by atmospheric friction to speeds of a few hundred kilometers per hour, and so hit the Earth with no more speed than if they had been dropped from a tall building. For meteorites larger than a few hundred tons (which fortunately are quite rare), atmospheric friction has little effect on the velocity and they hit the Earth with the enormous speeds characteristic of their entry into our atmosphere. Thus, for example, it is estimated that the meteorite that produced the Barringer Crater was still travelling at 11 km/second when it struck what is now the Arizona desert 49,000 years ago. Such objects do enormous damage, because the kinetic energy carried by the meteorite is the product of the mass and the square of the velocity. There is no documented record of a human being killed by a meteorite, but in recent years meteorites have crashed into bedrooms in Alabama, dining rooms in Connecticut, and a car in New York

Source

and one more

An asteroid has an average orbital speed (how fast an object orbits the sun) of 25 kilometers per second. However, asteroids orbiting closer to a sun will move faster than asteroids orbiting between Mars and Jupiter and beyond. The closest orbiting asteroid found so far is 2004 JG6 with an approximate orbital velocity of over 30 kilometers per second. It was discovered at the Lowell observatory on May 10, 2004.

Source

WWow Rez, I, again, am blown away by one of your threads. Very well put together. I am looking forward to seeing Ison at the end of next year. They are saying that it is supposed to put on a great show. And be brighter than the full moon.

Hale-Bopp was pretty cool to see, The are meteor showers in the next couple of days??? Where is the best place to see them?
There is one that is supposed to graze our satallites on Janurary, of Feburary 13th.

reply to post by Rezlooper


Regardless it is much more reliable than your sources
ATS'ers may not trust it but many have quoted it. Strange huh ?
Forgive me if I trust a well credited global website against 1 quote from you.
As you see in the evidence you quote the speeds are much slower.

reply to post by thepolish1


Quadrantid meteor shower peaks Jan. 3. Peak times at night are midnight to dawn and the radiant is in the north sky. The showers will be more difficult to see because the moon rises during those times as well.

The annual Quadrantid meteor shower is expected to produce its greatest number of meteors in the wee hours before dawn tomorrow: Thursday, January 3. Before dawn on January 4 might also be a possibility – especially for far eastern Asia. This year, 2013, the waning gibbous moon will be in the sky during the peak hours for watching meteors. But you might see some of the brighter meteors, even in moonlight. The Quadrantid meteor shower is capable of matching the meteor rates of the better known August Perseid and December Geminid showers. It has been known to produce up to 50-100 or more meteors per hour in a dark sky. This shower favors the Northern Hemisphere. That’s because its radiant point – the point in the sky from which the meteors appear to radiate – is far to the north on the sky’s dome.

Source

If you want to see them;

You need a dark, open sky, and you need to look in a general north-northeast direction for an hour or so before dawn. That’s the Quadrantid meteor shower – before dawn January 3, 2013 – for the world’s northerly latitudes. If you’re in Asia, you might try between midnight and dawn on January 4 as well. Who knows? Some of the Quadrantids meteors might be bright enough to dazzle you, even in bright moonlight.

Originally posted by cody599
reply to post by Rezlooper

 

Regardless it is much more reliable than your sources
ATS'ers may not trust it but many have quoted it. Strange huh ?
Forgive me if I trust a well credited global website against 1 quote from you.

Dude, I just gave you three 'global' websites, strange huh?

reply to post by Rezlooper


Three sites that all quote slower speeds.
Dude

reply to post by thepolish1


Here is a much better short article about the Quadrantids this week starting Tuesday night.

Being a fan of winter meteor showers requires a lot of hope and patience. There are plenty of opportunities to be wowed by the celestial displays, but there also are plenty of clouds. However, if the weather cooperates, the Quadrantid meteor shower will reach its peak Thursday night and Friday morning. Considered an above-average shower, the Quadrantids can have up to 40 meteors per hour at its peak. Even though the shower peaks later in the week, meteors can be visible from Tuesday through Saturday. Also effecting the viewing, a near-last-quarter moon will hide many of the fainter meteors with its glare. The best viewing will be at a dark location after midnight. Look for meteors radiating from the constellation Bootes. Read more here: www.thenewstribune.com...=cpy

Originally posted by Rezlooper
reply to post by FireballStorm

 

two more Earth-grazers this year alone. Whoa.

Just to clarify - a distinction should be made between these relatively large and rare "meter-class" random earth grazing asteroids or asteroid fragments. Meteor showers and random (or "sporadic") meteors that may be anywhere from dust/sand-grain sized up to "pebble-sized", which are mostly the debris ejected from comets probably account for many thousands of small (though still impressive when you see them) earth grazing meteors every year.

Originally posted by Rezlooper
reply to post by FireballStorm

 

I'll be doing some skywatching over the next few days with this new meteor shower.

I'm not sure the NYE prediction will be the right timing for you (North American observers in general) - Trying to work out time-zones makes my head spin!

Even if the predicted timing of the peak is not right for you, there is a fair chance that the timing may be off by a few hours since very little is known about this shower due to lack of observations, so it's worth a try.

Originally posted by Rezlooper
reply to post by FireballStorm

 

Maybe I'll get to see one of these in my lifetime as well.

If you are determined to see them, I don't see any reason why you should not. It may take a few meteor showers, but they are well worth the wait

Originally posted by Rezlooper
reply to post by FireballStorm

 

And how were you so fortunate enough to catch that photo?

It's a long story, but I enjoy telling it, and I'll try and condense it down a bit...

For me, it all started in November 1998, when by chance I heard on the news that the Leonid meteor shower was going to take place in a few nights time. Being enthusiastic, and having never experienced a proper meteor shower, I decided to keep an eye out on the night before the predicted peak. I could not believe my luck when I looked out of my window an hour or two before midnight, and saw a bright meteor within a few seconds, and then another just seconds later. This "fireball storm" continued throughout the night, and I was even seeing fireballs just before sunrise when the sky was getting very bright.

Over the following days I did some research on the internet and found out that the Leonids that year had caught almost everyone out, and an unexpected outburst of fireball class meteors had occurred 24 hrs earlier than expected than the regular Leonid peak.

As my interest in the subject grew, I found out that some researchers were predicting further storms and outbursts from the Leonids. Again I was lucky as computer modelling of meteor shower dust trails was just starting to come of age, so in 2001 I took a chance and flew to the other side of the planet with my 2 trusty Nikon 35mm SLRs.

Since storm levels had been predicted, I knew that there was a high probability of seeing earth grazing Leonids while the radiant was rising. All I had to do was set up my cameras at the observing site, and wait. The predictions turned out to be spot on, and as the radiant neared the horizon, we started to see the first grazers. As the night progressed, the grazers turned into normal meteors, and at the peak of the storm there were times when 5 or 6 meteors were observed at the same time. That was amazing to witness in it's self, but for me the highlight was the super-long fireball magnitude grazers!

The moral of the story is, if you want to see grazers, the best chance is during an outburst or storm, although you might get lucky and see them during one of the stronger annual meteor showers. If things don't pan out over the next few days, you may be in luck, as there is the possibility of a strong outburst or even a storm from another newly discovered meteor shower in 2014.

You just need to make sure that you are in the right place at the right time. Be warned though, the weather can easily spoil plans to observe. It helps if you can check the forecast/satellite images 10-12 hrs in advance and then travel to a location that looks like it will be clear.

reply to post by FireballStorm



Great story. I'm in the central time zone in northern WI, do you know when the best time is for this shower?