On 6th October 2008, asteroid hunter Richard Kowalski saw something that would change the assessment of threats presented by asteroid impacts. The night was proceeding normally and up on the screen came another asteroid. As I continued to make observ...
Tim has developed a map to visualize their location. And on that map, the most important are the Near-Earth asteroids, the ones closest to the planet. On the screen here is a map of the solar system. And Ive got the Sun in the centre and the third pl...
Luckily, the very biggest asteroids are few and far between. But there are still plenty of rocks out there that represent a significant danger to us. So, at the summit of an extinct Hawaiian volcano, Professor Nick Kaiser and his colleagues are searc...
The meteorite was 15 kilometres across, enough to cause utter devastation across the whole planet. It exploded with a force of 100 million million tones of TNT. The blast sent a giant plume of vaporized rock out into space. A crater was punched 30 ki...
As the divers have explored further, they discovered the Siluteis are actually part of a huge complex of tounels and caves.In fact, when you look from above, you can see Senluties scattered across hundreds of kilometers.And when they were mapped, it...
Look at the size of this! This is magnificent! That is beautiful. This cave may be stunning, but it provides the evidence for one of the greatest catastrophes in the Earths history. And that water, its so clear! Lower the gear, please! Theres actuall...
Comparing the effects of an airburst with a ground strike, it seems the Chelyabinsk got away lightly. Its estimated that the largest piece to hit the ground weighed 500 kilos, a fraction of the asteroids original mass of 7,000 tonnes. Now if a piece...
Oh, perfect, perfect, perfect. Now were seeing the fireball come in, its brighter than the Sun and then, Kapow, it hits the surface. Jeez! This whole region, downrange, would have been incinerated. It would have been incinerated just by this plasma,...
So this was serial number one. It was built during the Apollo time. I guess because they thought there would be several of them made, but this is the first one and the last one and is the only one like it in the world. This is NASAs Vertical Gun Rang...
Down on the ground, the scale of impact is even more breathtaking.The crater is more than 1000 meters across and nearly 200 meters deep.The forces here were enoumous.The impact on this solid rock into this pulverized mochi,just bustled in your hand.Y...
Really, its a balance between the size of the object, its speed into the atmosphere and critically the altitude at which it explodes. Too high, if its too small and it explodes too high, the shockwave has little effect on the ground. If its quite low...
Most of the damage from an explosion like this is actually the blast wave. Its the very high winds. Mark created a simulation to see what size an asteroid would need to be to be able to generate such destructive power. In this simulation I include mo...
On June 30th, 1908, a huge explosion tore through the forest of Tunguska, Siberia. It was 20 years before the Russians mounted an expedition to the site. What they found astonished them. 60 million trees across an area the size of London had been lev...
So was this a near miss for us? If the asteroid had been in a different part of its orbit, so it didnt hit this year but it hit next year, it would have still hit us on February 15th. But instead of coming in over Russia, it would have come in over t...
There it is! Yep. Its about 90 kilometres up, at that stage, travelling at 17.5 kilometres per second. Using the different camera positions, scientists have pinpointed the exact position at which the meteor entered the atmosphere. And by tracking the...
