Skip to main content

A 500-Meter-Long Asteroid Flew Past Earth, and Astronomers Were Watching

An asteroid the size of the Empire State Building flew past Earth in early February, coming within 1.8 million km (1.1 million miles) of our planet. Not only is it approximately the same size as the building, but astronomers found the asteroid – named 2011 AG5 — has an unusual shape, with about the same dimensions as the famous landmark in New York City.

“Of the 1,040 near-Earth objects observed by planetary radar to date, this is one of the most elongated we’ve seen,” said Lance Benner, principal scientist at JPL who helped lead the observations, in a JPL press release.

This extremely elongated asteroid has a length-to-width ratio of 10:3.

The orbit of asteroid 2011 AG5 carries it beyond the orbit of Mars and as close to the sun as halfway between Earth and Venus. Image credit: NASA/JPL/Caltech/NEOPO

Since there was no risk of this asteroid hitting our planet, astronomers took the opportunity to study 2011 AG5, as this is the closest pass the asteroid has made to Earth since its discovery in 2011. Radar observations revealed the object was about 1,600 feet (500 meters) long and about 500 feet (150 meters) wide.  The Empire State Building is 1,454 ft (443 meters) tall –counting the spire and antenna — and 187 ft (57 meters) wide.

The asteroid passed about five times the distance between the Earth and the Moon. 2011 AG5 will have another close flyby in 2040 when it comes within three times the Earth-Moon distance.

In years past, astronomers usually called upon the Arecibo radio observatory in Puerto Rico, which was the most sensitive system in the world for observing and detecting near-Earth asteroids. But since the observatory’s collapse in 2020, astronomers have called upon the less-sensitive but more flexible Goldstone radar in California – part of the Deep Space Network —  to conduct follow up observations on asteroids.

Using radar, astronomers can measure the distances, sizes, and spin rates of asteroids.

The observations revealed the surface of 2011 AG5 has subtle dark and lighter regions that may indicate small-scale surface features a few dozen meters across. If seen by the human eye, it would resemble charcoal. It’s rotating slowly, taking about 9 hours to make a complete spin.

The 70m telescope at the Goldstone Deep Space Communications Complex in California’s Mojave Desert. (NASA/JPL)

Astronomers said beyond contributing to a better understanding of what this object looks like up close, the Goldstone radar observations provide a key measurement of the asteroid’s orbit around the Sun. Radar provides precise distance measurements that can help scientists at NASA’s Center for Near Earth Object Studies (CNEOS) refine the asteroid’s orbital path. Asteroid 2011 AG5 orbits the Sun once every 621 days and won’t have another close encounter with Earth until the 2040 flyby.

“Interestingly, shortly after its discovery, 2011 AG5 became a poster-child asteroid when our analysis showed it had a small chance of a future impact,” said Paul Chodas, the director for CNEOS at JPL. (Read about the uncertainties in this 2012 article). “Continued observations of this object ruled out any chance of impact, and these new ranging measurements by the planetary radar team will further refine exactly where it will be far into the future.”

The post A 500-Meter-Long Asteroid Flew Past Earth, and Astronomers Were Watching appeared first on Universe Today.



from Universe Today https://ift.tt/MiUnCc7
via IFTTT
Labels:

Comments

Post a Comment

Popular posts from this blog

Researchers Match Up 12 Meteorites with the Near-Earth Asteroids They Came From

Every day meteoroids blast through our planet’s atmosphere to hit the ground as meteorites. A team of researchers in Italy traced twelve of them to progenitor asteroids that orbit in near-Earth space. Scientists treasure meteorites because they reveal information about their parent bodies. In an arXiv paper, two Italian researchers—Albino Carbognani and Marco Fenucci—analyze the characteristics of the parent bodies of 20 selected meteorites. They were able to track all but eight back to their parent asteroids. Based on their work, the pair says at least a quarter of meteorites come from collisions that happened in near-Earth space and not in the Main Belt. Meteorites from Near-Earth Asteroids: How They Got Here Many meteorites are chondritic, similar to asteroids in the Main Belt (or came from it). In their paper, the authors point out that progenitor meteoroids (including many that fall to Earth and become meteorites) formed millions of years ago following collisions between main-...
Post a Comment
Read more

JWST Takes a Detailed Look at Jupiter’s Moon Ganymede

Nature doesn’t conform to our ideas of neatly-contained categories. Many things in nature blur the lines we try to draw around them. That’s true of Jupiter’s moon Ganymede, the largest moon in the Solar System. The JWST took a closer look at Ganymede, the moon that’s kind of like a planet, to understand its surface better. Ganymede is basically a planet, except it doesn’t orbit the Sun. If it did orbit the Sun instead of Jupiter, it would be indistinguishable from a planet. It has a differentiated internal structure with a molten core that produces a magnetic field. It has a silicon mantle much like Earth’s, and has a complex icy crust with a deep ocean submerged beneath it. It has an atmosphere, though it’s thin. It’s also larger than Mercury, and almost as large as Mars. According to the authors of a new study, it’s an archetype of a water world. But even with all this knowledge of the huge moon, there are details yet to be revealed. This is especially true of its complex surface...
Post a Comment
Read more

The Ultraviolet Habitable Zone Sets a Time Limit on the Formation of Life

The field of extrasolar planet studies has grown exponentially in the past twenty years. Thanks to missions like Kepler, the Transiting Exoplanet Survey Satellite (TESS), and other dedicated observatories, astronomers have confirmed 5,690 exoplanets in 4,243 star systems . With so many planets and systems available for study, scientists have been forced to reconsider many previously-held notions about planet formation and evolution and what conditions are necessary for life. In the latter case, scientists have been rethinking the concept of the Circumsolar Habitable Zone (CHZ). By definition, a CHZ is the region around a star where an orbiting planet would be warm enough to maintain liquid water on its surface. As stars evolve with time, their radiance and heat will increase or decrease depending on their mass , altering the boundaries of the CHZ. In a recent study , a team of astronomers from the Italian National Institute of Astrophysics (INAF) considered how the evolution of star...
Post a Comment
Read more