How big is the largest object ever to have hit earth?

Answer 1

One of the clearest sign of a massive impact was massive extinction of life. The greatest extinction event sometimes called the Great Dying was the Permian-Triassic extinction. It occurred approximately 251 million years ago (mya), forming the boundary between the Permian and Triassic geologic periods. It was the Earth's most severe extinction event, with about 96 percent of all marine species and 70 percent of terrestrial vertebrate species becoming extinct. Recently, a 300-mile-wide crater was discovered in the Wilkes Land region of East Antarctica, which is believed to be linked with the extinction.

A 300-mile-wide crater more than a mile beneath the East Antarctic Ice Sheet was found using gravity fluctuations measured by NASA's GRACE satellites to peer beneath Antarctica's icy surface, imaging a 200-mile-wide plug of mantle material—a mass concentration, or "mascon" in geological parlance—that occurs within the Earth's crust and appears to have been emplaced somewhere between 100 and 500 million years ago—a broad time span that brackets the specific age of the Permian-Triassic extinction.

When the scientists overlaid their gravity image with airborne radar images of the ground beneath the ice, they found the mascon perfectly centered inside a circular ridge some 500 km (300 miles) wide. The Wilkes Land crater is more than twice the size of the Chicxulub crater in the Yucatan peninsula, which marks the impact that may have ultimately killed the dinosaurs 65 million years ago. The Chicxulub impactor (most likely an asteroid) is thought to have been 6 miles wide, while the Wilkes Land impactor (either an asteroid or perhaps a large comet nucleus) could have been up to 30 miles wide—four or five times as wide.

Answer 2

We are limited to observable data, so a definite answer may not be possible. As our knowledge stands now, there are 2 leading possibilities.

1. The K-T Meteorite, which is believed to have formed the gulf west of the Yucatan Peninsula in Mexico. This collision, 65 million years ago, is believed by many scientists to have helped cause the demise of the dinosaurs. Estimates of its size range from 8-10 km in diameter.

2. The leading hypothesis for the formation of the Earth's Moon suggests that a planet-sized object the size of Mars struck the Earth, ejecting large volumes of matter. A disk of orbiting material was formed, and this matter eventually condensed to form the Moon in orbit around the Earth. If this hypothesis is correct, then the largest object to hit the Earth would probably be this Mars-sized object, occurring during the Solar System's formative period up to 4.5 billion years ago.

Answer 3

The rock, catalogued as 2004 MN4, was discovered last June. It was seen again in December, and for a time scientists said it had the highest odds of hitting Earth ever given to a space rock. Subsequent observations refined the future path and eliminated those odds for the 2029 flyby. It won't hit the Moon, either.

This week, NASA scientists used new observations from the Arecibo Observatory to further pin down the track of 2004 MN4.

On April 13, 2029, it will be about 22,600 miles (36,350 kilometers) from Earth's center. That is just below the altitude of geosynchronous satellites, which hover in fixed perches above the planet to communicate with and collect data on half the globe at all times.

Of the ten known closest asteroid flybys, 2004 MN4 is by far the largest object, said Steve Chesley of NASA's Jet Propulsion Laboratory. Only two have come closer, and they were only tens of yards (meters) wide.

"All of the others in the top ten were discovered during the close approach, whereas for 2004 MN4 the close approach is predicted well in advance," Chesley said in a telephone interview.

Last fall, an even larger asteroid made a notable flyby. That rock, called Toutatis, is about 2.9 miles long and 1.5 miles wide (4.6 by 2.4 kilometers). Its closest approach, widely photographed, was about four times the distance to the Moon. It was not visible to the naked eye.

Answer 4

Probably the object that collided with the Earth, forming the Moon, but the earth then wasnt the blue marble we know today, it was a still molten ball of rock and metal...

"The Giant Impact hypothesis holds that the Moon formed from the ejecta resulting from a collision between a very early, semi-molten Earth and a planet-like object the size of Mars, which has been referred to as Theia or Orpheus. The material ejected from this impact would have gathered in orbit around Earth and formed the Moon. This hypothesis is bolstered by two main observations: First, the composition of the Moon resembles that of Earth's crust, whereas it has relatively few heavy elements that would have been present if it formed by itself out of the same material from which Earth formed. Second, through radiometric dating, it has been determined that the Moon's crust formed between 20 and 30 million years after that of Earth."

Answer 5

an asteroid that hit millions of years ago when the dinosaurs roamed.. people believe that from the impact of the explosion it wiped out the dinosaurs.. So an asteroid falling from space and wiping out a whole entire species has got to be the largest.

Answer 6

they think a meteor hit the gulf of mexico which has yet to be proven. they did find a crater recently near australia that is the size of rhode island that they now know hit earth and caused destruction. how far back and to what extent they are working on.

Answer 7

Some say the moon is a combo of an asteriod, and debri from the earth from the asteriod hitting it:

The moon

Answer 8

May be one fourth the size of the earth??

Answer 9

the meteorite that hit the gulf of mexico near where cancun is i forget the name but that is what they think killed the dinosaurs

Answer 10

Wierd, I was just thinking the same question