Explore Asteroids In Depth › Key Science Targets

Earth-orbit-crossing asteroids whose orbital semi-major axes are smaller than that of the Earth are called Aten asteroids (also after the first such asteroid discovered). Asteroid 2012 DA14 made a record-close pass -- 17,100 miles -- by Earth on February 15, 2013. They orbit … 1998 OR2 will fly by Earth at a distance of 3.9 million miles (6.3 million kilometers) on April 29. Asteroids range in size from Vesta — the largest at about 329 miles (530 kilometers) in diameter — to bodies that are less than 33 feet (10 meters) across. While it may sound like something out of anime, this "Atira" asteroid is very real. Most asteroids are made of rocks, but some are metal.

The Arecibo Observatory captured this radar image of the big asteroid 1998 OR2 on April 18, 2020.

New Asteroid Found PUiodically crosses Earth's orbit was recently discovered by JPL planetary scientist Eleanor Helin, who found the asteroid while photographing two components of rare split comet. Go farther. Note: Often, images posted on this site are slightly altered to enhance their web visibility, but ISAS/JAXA policy forbids such alterations, even by non-commercial sites such as this one. Most asteroids outside the "big four" (Ceres, Pallas, Vesta, and Hygiea) are likely to be broadly similar in appearance, if irregular in shape. The total mass of all the asteroids combined is less than that of Earth's Moon. Asteroids and comets are considered remnants from the giant cloud of gas and dust that condensed to create the sun, planets, and moons some 4.5 billion years ago. The asteroid has been calculated to be the best candidate known … Big, rare asteroid found making the rounds between Earth and sun.