The journal Science [Feb. 23, 2001] reported conclusive evidence that an asteroid smashed into Earth 250 million years ago and likely launched the age of the dinosaurs. The impact disaster wiped out 70 percent of land vertebrates and 90 percent of marine animals. The research performed by NASA, the National Science Foundation, and three leading universities, revealed a type of carbon structures called fullerenes in 251 million year old geological samples taken from Japan and China.

On June 1, 2006 scientists, using satellite data, discovered the 300-mile-wide crater buried more than a mile beneath the East Antarctic Ice Sheet in what's known as the Wilkes Land region of Antarctica.

65 Million B.C.E.:

In 1979 physicist Luis Alvarez, his son, geologist Walter Alvarez, and nuclear chemists Frank Asaro and Helen V. Michael from the University of California, Berkeley, began to publish their research regarding "Extraterrestrial cause for the Cretaceous-Tertiary extinction." In June 1980 the journal Science published the Alverez team's groundbreaking report titled, Extraterrestrial Cause for the Cretaceous-Tertiary Extinction. The team had discovered unusually high concentrations of iridium, an element that's rare on the Earth but common in meteorites. From the amount and distribution of iridium present in the 65 million year old "iridium layer", the Alvarez team estimated that an asteroid about 5 milies wide (10–14 kilometers) must have collided with the Earth. This iridium layer has been found worldwide at 100 different sites.

In 1981, exploring for oil reserves in Yucatan, Mexico, Penfield and Camargo recognized that the gravity and magnetic anomalies centered on the village of Chicxulub, at the tip of the Yucatan peninsula in Mexico, resemble those identified at large impact structures. But it was only in 1991, that Hildebrand et al., proposed that the long sought impact crater lied buried under 1000 m of Cenozoic sediments at the tip fo the Yucatan peninsula. During the following years, the crater origin of the structure was demonstrated by geophysical and lithological studies and its age determined by radiometric dating (Swisher et al. 1992; Sharpton et al. 1993). The northwestern part of the crater lies offshore of the Yucatan peninsula. Onshore the crater rim is marked by a line of cenote (Pope et al, 1996).

48,000 B.C.E.:

A meteor about 50 meters (54 yards) across impacts the desert near what is now Flagstaff, Arizona, leaving a crater about 1,200 m (4,000 ft) in diameter, some 170 m deep (570 ft),

10,900 B.C.E.:

In June 2007 University of South Carolina News reported: Comet Theory Collides with Clovis Research, May Explain Disappearance of Ancient People:

"A theory put forth by a group of 25 geo-scientists suggests that a massive comet exploded over Canada, possibly wiping out both beast and man around 12,900 years ago, and pushing the earth into another ice age. Archaeologists have long known that the great beasts of the age - the wooly mammoth and mastodon - suddenly disappeared around the same time period (12,900 - 12, 800 years ), but little was known about their demise. The notion that a comet collided with Earth and caused these events was farfetched until recently, when the group of scientists began looking for evidence of a comet impact, which they call the Younger - Dryas Event.

"They turned to University of South Carolina archaeologist Dr. Albert Goodyear and the pristine Clovis site of Topper. In 2005, Arizona geophysicist Dr. Allen West and his team traveled to Topper in hopes of finding concentrations of iridium, an extra-terrestrial element found in comets, in the layer of Clovis-era sediment. 'They found iridium and plenty of it,' said Goodyear. 'The high concentrations were much higher than you would normally see in the background of the earth's crust. That tends to be an indicator of a terrestrial impact from outer space.' The researchers also found high iridium concentrations at six other Clovis sites throughout North America, as well as in and along the rims of the Carolina Bays, the elliptically shaped depressions that are home to an array of flora and fauna along South Carolina's coast. The Younger-Dryas Event suggests that a large comet exploded above Canada, creating a storm of fiery fragments that rained over North America. The fragments could have easily killed the giant mammals of the day, as well as Clovis man.

"'No one has ever had a really good explanation for the disappearance of mammoth and mastodon,' Goodyear said. 'The archaeological community is waking up to the Younger-Dryas Event.' The comet theory dominated the recent annual meetings of the American Geophysical Union held in Mexico. Goodyear's Clovis-Redstone point study and West's research on the comet were featured at the AGU meetings and by the journal, Nature. The comet will be the subject of documentaries featured on the National Geographic Channel and NOVA television late this fall [2007] and in early 2008."

8498 B.C.E.:

German physicist, Otto Muck, analyzed the elaborate calendar of ancient Mayan Indians and established that its purpose is to commemorate the date and time of impact of an asteroid that crashed into the Atlantic Ocean more than ten thousand years ago. In his book, The Secret of Atlantis, Muck concludes that the impact coincided with a conjunction of the Sun, Moon, and Venus. This triple conjunction enabled a calculation of orbits to find the exact moment of impact: 20:00 hours local time on June 5, 8498 B.C.E. From this cataclysmic moment over 10,500 years ago, marked by a triple conjunction, ancient Mayans counted the days and years of their calendar. The impact and tidal waves produced the story of Atlantis, as well as the biblical flood of Noah, and the legend of Gilgamesh.

536 C.E.:

Restricted tree ring growth across world forests after 536 C.E. is among evidence scientists provide to prove that an asteroid collided with Earth and the result was the Dark Ages. Astronomical records in Europe coincide with simultaneous records in China which report impact winter conditions that enveloped the world for 18 months. The space rock's entry into the atmosphere gave rise to folk tales of dragons - long tailed, fire breathing lion's heads speeding through the sky. The comet or asteroid exploded in the atmosphere, creating a dense cloud that encircled the Earth and shut down photosynthesis. Tree ring records worldwide record the event.

October 8, 1871:

On the night of October 8, 1871 Peshtigo, a booming town of 1700 people was wiped out of existence in the greatest forest fire disaster in American history. Loss of life, and even property, in the great fire occurring the same night in Chicago, did not match the death toll and destruction visited on Peshtigo in Northeast Wisconsin.

"The reason no one can explain these great fires is that no one knew to look to the heavens," explains scientist Randall Carlson, "But recent tests have shown that a comet nucleus only a hundred yards in diameter exploding 20 miles up in the atmosphere can set a large pine forest on fire. This is the only explanation that can account for the simultaneous outbreak of massive forest fires all over the mid west on October 8, 1871."

In fact astronomers at that time were tracking the dying comet Viala whose orbit was dangerously close to Earth. Some scientists have suggested that fragments falling from the comet may have ignited not only the Chicago fire, but the fires in neighboring states as well. The most deadly fire that night was not in Chicago, but in the small town of Peshtigo. Twelve hundred people died there in the worst fire in American history. A mass grave commemorates the remains of victims burned beyond recognition."

Robert Couvillion is the president of the Peshtigo Historical Society. The stories he has preserved are of a fire unlike any other: "Fire is not unusual in this territory, but on this particular night, this was a fire like nobody had ever seen. It was 7 or 8 o'clock at night when it became dark and they could see this glow in the western sky. It was like a muddled thunder that never ceased, it just kept growing louder and louder. Trees were being uprooted and roofs were coming off of the homes, chimneys were crashing to the ground. Everything was moving horizontally. It was like the heaviest snow storm you've ever seen, only it contained the burning embers and the ashes and the red hot sand and the dirt that was picked up. When they decided it was time to go to the river, already it was too late."

Before they could run, a firestorm blasted them off their feet. Clothing and hair combusted spontaneously. The air itself seemed to be on fire.

"Eyewitnesses described that the very sky itself was on fire as far as the eye could into space," said Randall Carlson. "Eyewitnesses described fireball and meteor-like phenomena falling from the sky just prior to the outbreak of the fire. In the aftermath they described whole forests of great maple trees uprooted and laid flat like new mown hay. This is strikingly suggestive of the forests knocked flat at Tunguska (Russian meteor impact site, June 30, 1908). While no one was killed at Tunguska, twelve hundred people lost their lives at Peshtigo."

June 30, 1908:

The Taiga meteorite impacts the Tunguska River in Siberia.

August 13, 1930:

A massive asteroid explodes over western Brazil and is reported in South American newspapers.

February 1936:

A large asteroid named Adonis passed within 186,000 miles of Earth, so close that it was nearly captured by our planet's gravity. Had it fallen it would have wrought destruction equal to several nuclear explosions.

1937:

Three small asteroids exploded in tremendous fireballs a mile above the jungle floor of Brazil, igniting a ground fire that destroyed over 800 square miles of rain forest.

September 1985:

An asteroid the size of several football fields comes within 1.5 the distance of the Moon from the Earth. This incident was referred to in January 2008 when another similar asteroid, 2007 TU24, was discovered heading for a similar near miss of Earth.

March 22, 1989:

An asteroid came within 400,000 miles of Earth, and was within 6 hours of striking the Earth, but was not detected until later. Other asteroids have come even closer, one would have hit the Earth if it had come just 4 hours sooner.

"In 1989 we had an asteroid pass us at only 690,000 miles away...and in 1991 the Earth came perilously close to yet another encounter with an asteroid. This asteroid passed the Earth at a distance of only 106,000 miles...These asteroids just barely missed us. Had they been at just a slightly different path, or been traveling at just a tiny different speed, the human race and much of the life on our planet would be gone now...These two most recent close passes by asteroids were discovered only a couple of months before they would have hit."