Lunar escape velocity averages 2.38 km/s (1.48 miles per second), only a few times the muzzle velocity of a common rifle (0.7-1.0 km/s). How did lunar meteorites get here?īecause the Moon has no atmosphere to stop them, meteoroids strike the Moon every day. In other words, they are rocks found on Earth that were ejected from the Moon by the impact of an asteroidal meteoroid or possibly a comet. Lunar meteorites, or lunaites, are meteorites from the Moon. A few rare meteorites come from the Moon (0.7%) and Mars (0.5%). Most (99%) recovered meteorites are pieces of asteroids. A meteor is the visible streak of light that occurs as the rock passes through the atmosphere and exterior of the rock is heated to incandescence. A meteoroid is what we call the rock while it is in orbit and before it is decelerated by the Earth’s atmosphere. Any major impact would lead to widespread damage, injury, and death, and would create unparalleled humanitarian and refugee crises around the world.List of lunar meteorites What is a meteorite?Ī meteorite is a rock that was formed elsewhere in the Solar System, was orbiting the sun or a planet for a long time, was eventually captured by Earth’s gravitational field, and fell to Earth as a solid object. An impact on or over a densely populated city could cause millions of deaths, and an impact on water could cause massive flooding on coastlines. The Next Event?Īlthough immense impactors like the one that devastated the entire planet 65 million years ago are rare, NEOs of many different sizes can pose serious threats. Perhaps more significantly, the dust could also have lingered in the atmosphere, blocking out the Sun and interrupting the photosynthesis of plants that the entire food chain depends on, as well as cooling the temperatures of the Earth for many years. ![]() ![]() This dust could have covered the entire surface of Earth for up to a decade, creating a harsh environment for living things. A cloud of super-heated dust, ash and steam would have spread from the crater as the impactor slammed underground in less than a second. Meanwhile, colossal shock waves would have triggered global earthquakes and possibly volcanic eruptions. It is possible that all of Earth’s forests burned. Like millions of shooting stars, all this material would have been heated to incandescence upon re-entry, heating Earth's surface and igniting wildfires. The blast would have thrown chunks of the asteroid and Earth so far that they would have briefly left the atmosphere before falling back to the ground. The asteroid hit in water, creating mega-tsunamis reaching from southeastern Mexico all the way to Texas and Florida and up a shallow interior ocean that covered what is now the Great Plains. The impact killed 70% of all species on Earth, including the dinosaurs.Īn impact of that size would have had devastating effects, and the geological record gives us some indication of what happened. The shock wave, traveling at the slower speed of sound, arrived later and shattered the windows, injuring people with flying glass.Ħ5 million years ago an asteroid roughly 10 to 15 kilometers (6 to 9 miles) in diameter hit Earth in what is now Mexico. Most of the injuries were caused by curiosity: people saw the bright flash and walked to windows to look outside. Still, it created a shockwave that injured 1,500 people and damaged 7,200 buildings across six cities. Luckily it exploded about 30 kilometers above ground and did not cause direct impact damage. It exploded while it was still in the air, releasing the same amount of energy as 500 kilotons of TNT. In 2013, an asteroid about 20 meters in diameter entered Earth’s atmosphere above the city of Chelyabinsk, Russia. ![]() The vast majority of these impacts were from very small objects, but there have been some remarkable exceptions. Asteroid impacts are natural processes that shape the surface of our planet, like volcanoes. Throughout Earth’s history, there have been many instances of near-Earth objects (NEOs) impacting our planet, either reaching the surface or exploding above ground from the intense energy released as the object passed through the atmosphere.
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