New answers tagged

1

Impacts typically occur at a range of 20 to 70 km/s. Let's look at the 20 km/s one. 1 kg of mass at 20 km/s = 1kg * 20,000 m/s * 20,000m/s /2 = 200 million joules. To bring ice from absolute zero to melting point requires 1000 * 273 * 0.5 = 136 thousand joules. Yes, melting it will take energy and so will vapourization, but this is VERY small potatoes ...


0

While comets are cold out in space they dissipate as they get closer to the sun and earth. Upon contact with the atmosphere they burn up. If a comet is large enough bolide they may possess the same climatological concerns as the Cretaceous asteroid impact


11

For your purpose (energy in the entire system) it doesn't matter if the asteroid lands gently or not because energy is conserved: If the asteroid slows through some kind of atmospheric braking, then the energy goes into the atmosphere as heat. If it slows through running into the ocean at full tilt then the energy goes into the ocean as heat. If the energy ...


4

Thermodynamically No Jean-Marie gives a good answer about aerosol effects. Others observe that impacts add energy to the planet. I would simply like to look at the energy budget. The sun dumps on the order of 173 petawatts on the earth, nonstop. Now, asteroids have a heat capacity on the order of $10^{18} - 10^{24} J/K$, depending on size. Note that a ...


19

I'm gonna sail against the wind and say "yes", indirectly. Although you don't need a cold asteroid, a "normal" one would suffice. When striking the Earth, asteroids eject a large amount of dust into the atmosphere, blocking the Sun radiations, thus cooling the planet. The phenomenon is known as impact winter and is similar to volcanic and ...


21

Could an icy/extremely-cold asteroid/comet ever strike and cool the Earth? No. The smallest possible velocity is about 11 km/s velocity, and that would require a near miracle. For that to happen, the object would have to enter the vicinity of the Earth through a very small keyhole near the Sun-Earth L1 or L2 point with a very small velocity (a comet will ...


4

One asteroid or comet, no. Even it it was huge you might get a planetary extinction event like the meteorite that crashed into the Yucatan region resulting in the dinosaurs dying out. That would be due to the amount of dust and soil etc. that would be thrown into the atmosphere. The other thing, as the asteroid/comet/meteorite entered the Earth's atmosphere ...


12

No, it's not possible to cool the Earth with an asteroid impact. The mass of any asteroid that could hit the Earth is far too small to be a heat sink. The asteroid that killed the dinosaurs had a mass of around $10^{16}$ kg. The Earth has a mass of $10^{24}$ kg, or a 100 million times more. And no matter how cold an asteroid is, the kinetic energy ...


Top 50 recent answers are included