Tiny Asteroid 2018 LA Hits Earth Hours After Discovery

Earthlings had only a brief visit from 2018 LA before it exploded in the planet’s atmosphere. These photos were made on June 2 by the Richard Kowalski of the Catalina Sky Survey using a 60-inch reflecting telescope located atop Mt Lemmon in the Santa Catalina mountains outside Tucson. The four images were combined into a 4-frame movie. The asteroid appears streaked because it was close to the Earth and moving swiftly. Catalina Sky Survey

For only the third time, astronomers have discovered an asteroid just hours before it crashed to Earth. That’s exactly what happened on June 2. Richard Kowalski, senior research specialist for the Catalina Sky Survey based in Tucson Arizona, recorded and observed a fast-moving asteroid. From the observations he calculated an orbit predicting the object’s trajectory would take it straight into the atmosphere over southern Africa within a matter of hours.

Bill Gray of Project Pluto plotted the asteroid’s final hours above the Earth before it entered the atmosphere over southern Africa. Bill Gray

A little more than seven hours later at 16:53 Universal Time — early evening in eastern Africa —  2018 LA slammed into the atmosphere over Botswana, a small country which borders South Africa. Eyewitnesses described a orange-and-red, sparking fireball nearly as bright as the sun that exploded in two bright bursts over the countryside. Some heard rumbles like thunder in its wake, while an infrasound recorder in South Africa registered the explosion’s low frequency sound waves. Based on their strength, scientists estimate the asteroid measured between 6.8 and 15 feet (2.1 – 4.6 meters) long and exploded with the power of 300-500 tons of TNT.

AMS head Mike Hankey believes that based on the current data meteorites may have fallen east of the town of Ghanzi in western Botswana. Google Earth

Right now, meteor hunters and scientists on the ground, are trying to gather as many reports as possible the better to narrow down the search for possible meteorites that likely survived the explosion. Mike Hankey, who runs the American Meteor Society website, a clearinghouse for bright meteor sightings, is actively seeking reports of the fireball. If you know of anyone who witnessed it, please ask them to fill out this report form. The sooner teams on the ground can look for and potentially gather up fragments the better. Newly fallen meteorites contain tiny amounts of rare, short-lived forms of elements called isotopes than can tell us where they came from and for how long they’ve been in space before they found their “new home” on Earth.

Dr. Peter Jenniskens finds fragments of the meteorites dropped by the asteroid 2008 TC3 in the Nubian Desert. The meteorite received the name Almahatta Sitta. Many fragments were found. Peter Jenniskens

What’s amazing is that the keen-eyed Kowalski has found all three of these self-destructing asteroids. 2008 TC3 was the first, a 4.1-meter object discovered on October 7, 2008 that exploded over Sudan’s Nubian Desert 19 hours later. After many eyewitness interviews, Peter  Jenniskens of the SETI Institute put together a search time. In time, more than 600 meteorites with a total weight of 10.5 kilograms were found. The second asteroid, 2014 AA, was nabbed by Kowalski on January 1, 2014 and plunked into the Atlantic Ocean northeast of Brazil about 21 hours later. It was about 10 feet (3 meters) across.

2018 LA became a brilliant meteor captured in this video taken with a security camera from a farm between Ottosdal and Hartebeesfontein, North West South Africa. Barend Swanepoel

Astronomers estimate there are a billion objects this size that cross Earth’s orbit. That’s why they’re called Earth-crossers. A few plunge out of the sky every year but most are only witnessed by satellites because they occur in daylight and over the broad expanse of the oceans, which take up 71% of planet’s surface area. When the hit the atmosphere at speeds in excess of 25,000 mph, they break up into dust or, if we’re lucky, into fragments that land as meteorites.

In this animation, we see can watch the 2018 LA track along its orbit until the time of its fateful Earth crossing. Click to start.

That’s what we’re hoping for from 2018 LA — a few fragments to sweeten our understanding of asteroids and how they helped build the solar system. I’ll keep you posted.

2 Responses

  1. I was indoors but a two colleagues of mine saw the event from two different locations about 100 – 120km apart. Would you be interested in their version of the event?

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