Huge Space “Peanut” Zips Past Earth

09 Aug 2015

Although the Earth is always “at risk” for an encounter with asteroids, comets and meteorites, this “peanut-shaped” asteroid made news when it flew past Earth at a whopping 45,000 miles-per-hour (72,420 kilometers-per-hour) near the end of July.

Named 1999 JD6 this asteroid caught the attention of NASA’s camera’s, not only for its closeness to our planet (a mere 4.5 million miles away; 7.2 million kilometers) but also for its odd peanut-like shape. Scientists are stating this chunk of debris is known as a “contact binary,” which is when an asteroid has two prominent lobes stuck together. According to Lance Benner, the lead NASA asteroid radar researcher; “Radar imaging has shown that about 15 per cent of near-Earth asteroids larger than 600 feet (180 metres), including 1999 JD6, have this sort of lobed, peanut shape.”

This collage of radar images of near-Earth asteroid 1999 JD6 was collected by Nasa on July 25, 2015.

What Is an Asteroid?

There are a lot of space rocks flying around in our galaxy and they all fall into different categories. Asteroids are defined as “small,” airless rocky worlds that are too small to be considered planets; however, they are sometimes referred to as planetoids or minor planets – it’s no wonder scientists get alarmed when one is detected heading towards Earth.

Asteroids are thought to be leftovers from the formation of the solar system with the creation of Jupiter. This planet is too large to allow the formation of other planets between itself and Mars, so the space rocks there collided with one another and became asteroids.

Most asteroids are found here in the “asteroid belt” that lies between the orbits of Mars and Jupiter. This “rocky” region contains upwards of 200 asteroids all larger than 60 miles (100 kilometers) in diameter. There are also smaller asteroids (about 750,000) that are less than one kilometer in diameter and many more even smaller in size. However, many asteroids do lie outside of this belt. The ones called Trojans lie along the orbital path of Jupiter and are broken into three groups; Atens, Amors and Apollos. These space rocks are also known as near-Earth asteroids because they orbit our inner solar system and will sometimes cross the path of Mars and Earth.

Albeit small in comparison to some asteroids, 1999 JD6 could have done some damage if it made contact with our planet (it was identified as being about 1.2 miles long (1.9 kilometers)).

Asteroids are pitted and irregular in shape. They are covered with dust and have a surface temperature of about -100 degrees Fahrenheit (-73 degrees Celsius). Since asteroids have remained the same for billions of years, scientists are always anxious to study them

Imagining Asteroid Technology

The technology that brought us the images of 1999 JD6 was no ordinary camera, but in fact a complex imaging system that uses two locations to capture the shots. A 230 foot (70 meter) antenna situated in Goldstone California called, the Deep Space Network, beamed a radar signal at the peanut asteroid. The reflection from our space-friend was then received by the 330 foot (100 meter) telescope (the National Science Foundation Green Bank Telescope) in West Virginia.

This imaging technique is called, bistatic observation, and dramatically improves the quality and detail of the images. In fact, the asteroid has details shot as small as 25 feet (7.5 meters) wide. In addition, the imaging was recorded for 7 hours and 40 minutes.

Sean Marshall, a graduate student at Cornell University in Ithaca, New York, is particularly interested in the radar imaging collected by this system for his doctoral research on 1999 JD6. He states;

“I’m interested in this particular asteroid because estimates of its size from previous observations, at infrared wavelengths, have not agreed. The radar data will allow us to conclusively resolve the mystery of its size to better understand this interesting little world.”

Radar imaging is far superior to ordinary photography as it allows deeper study into an asteroid’s size, shape, rotation, surface features, surface roughness, and also for improving the calculation of asteroid orbits.

With so much technology at our disposal science is not far behind in discovering all the mysteries of our galaxy and beyond. In the mean time, keep your telescopes and eyes pointed towards the night sky. Although 1999 JD6 won’t buzz around this close to Earth until the year 2054, you never know what other celestial wonders are just waiting to be discovered.