Astronomers Catch Asteroid Striking Moon On Video 69
spineas writes "A 4.5-foot-wide asteroid struck the moon in September 2013, and astronomers were lucky enough to catch the impact flash on video, now confirmed as the brightest ever witnessed from Earth. The Orlando Sentinel reports that the asteroid likely weighed nearly 900 pounds, and exploded on impact with the moon with the force of 15 tons of TNT."
Re:How do we disable the beta so we can read the s (Score:3, Informative)
My bookmark has said http://slashdot.org/?nobeta=1 [slashdot.org] since before the Slashcott.
Re:Units (Score:5, Informative)
The first link in the summary leads to the Orlando Sentinel, which links to the full video from the Universidad de Huelva. That video estimates "400 kg, 0.6-1.4 m object, 40 m crater, 61000 km/h, 15 tons of TNT". The first three are SI units, the fourth closely related, and the fifth... well, "tons of TNT" dates from the 20th century so how can we call it archaic? It's the Orlando Sentinel who translates into those archaic English units for US-ers such as myself. In the second link in the summary Phil Plait goes so far as to translate the crater size into football fields, but perhaps we shouldn't fault him as that standard unit is neither "English" nor "archaic".
For those who want to see the actual footage (Score:5, Informative)
The video is almost five minutes long and mostly computer animations. Actual footage of the moon can be found in three segments:
2:13 - 2:23 Examples of previous impact flashes
3:00 - 3:08 Full-speed MIDAS video of the big flash
3:20 - 3:30 Slow motion MIDAS video of the big flash
Re:Can someone please explain (Score:5, Informative)
...Why this impact apparently emitted so much light?
I get that the asteroid probably had a LOT of kinetic energy, but isn't it only in "Hollywood physics" that when two inert things collide you get a fiery explosion? .... and I'm even more surprised as it took place in a vacuum where my limetd understanding of conventional physics says fire cant happen...
You're underestimating what "a lot of kinetic energy" is when you're talking about speeds measured in km per second - and kinetic energy goes with the square of the velocity.
A lot of kinetic energy gets transformed into a lot of heat. Hot things give off light (they don't need to be "on fire") - fire gives off light because it is hot. A light bulb gives off light but it isn't on fire - but it is hot. Lightning isn't on fire. The sun isn't on fire. Probably what you see is most of the asteroid (and a chunk of the moon) getting turned into a plume of superhot gas, if not plasma.
No Hollywood physics involved, or there would have been a loud 'kaboom' at exactly the same time as the flash, a perfectly circular blue shockwave ring shooting out from the moon and Harrison Ford in a fridge.