New Fireball on Jupiter Spotted By Skywatchers
On Aug. 20, amateur astronomer Masayuki Tachikawa of Kumamoto city, Japan, spotted a fireball on Jupiter, and caught the apparent impact on video. In this compilation of high-resolution images created by John Rogers, director of the British Astronomical Association's Jupiter section, the planet is seen 1-2 rotations before and 1-2 rotations after the Aug. 20 fireball.
Credit: John Rogers [Full Story]

This story was updated at 2:05 p.m. EDT

Amateur skywatchers have spotted what appeared to be a new fireball from yet another apparent impact on Jupiter ? the third in 13 months for the gas giant.

Amateur astronomer Masayuki Tachikawa of Kumamoto city, Japan, caught the fireball on video Aug. 20, according to the website Spaceweather.com, which monitors space weather and other cosmic events.

Tachikawa spotted the fireball at 3:22 a.m. Japan Standard Time (1822 GMT, or 2:22 p.m. EDT). [High-resolution images of the fireball.]

A separate image of the fireball was later confirmed by another Japanese amateur astronomer, Aoki Kazuo of Tokyo. Kazuo recorded a flash on Jupiter at the same time and in the same place on the gas giant that Tachikawa did, Spaceweather.com reported.

In addition to supporting the likelihood of an impact, the separation between the two observers ? over 490 mile (roughly 800 km) ? excluded the possibility that the flash came from an event near Earth, explained Spaceweather.com's Tony Phillips.

Jupiter is no stranger to violent impacts.

The fireball came just 13 months after a spectacular crash that scientists now think involved an asteroid about 1,600 feet (500 meters) wide. The July 19, 2009, collision created a bruise on the planet the size of the Pacific Ocean.

On June 3 of this year, Australian amateur astronomer Anthony Wesley reported seeing a flash on Jupiter while watching a live video feed of the planet from his telescope. In the Philippines, amateur astronomer Chris Go confirmed the discovery from his own simultaneous video recording of the transitory event.

Astronomers around the world determined that some object must have whacked the gas giant in order to unleash a flash of energy bright enough to be seen 400 million miles (643.7 million km) away.

There was no visible scar or debris cloud from the June 3 impact, so astronomers were unsure how deeply the object penetrated into the atmosphere. The Hubble Space Telescope's sharp vision and ultraviolet sensitivity were called into action.

The Hubble Space Telescope's sharp vision and ultraviolet sensitivity was called into action to seek out any traces of the aftermath of the June cosmic collision.

Images taken June 7 showed no sign of debris above Jupiter's cloud tops. That suggests the object did not descend beneath the clouds and explode as a fireball, astronomers said.

"Like the event of June 3rd, this fireball did not produce any visible debris," John Rogers, director of the British Astronomical Association's Jupiter section, told Spaceweather.com. "As the observers commented, there was no visible mark (not in RGB, nor UV, nor methane), post-impact. Dark brown spots on the North Equatorial Belt were already there before the fireball."

The June 3 mystery fireball was later identified as a giant meteor that plunged into the planet's atmosphere and burned up high above its cloud tops, according scientists who used observations from the Hubble Space Telescope.

In 1994, the comet Shoemaker-Levy 9 broke into more than 20 pieces and pelted Jupiter repeatedly. At the time, astronomers estimated such impacts could occur on Jupiter every 50 to 250 years.

With the recent collisions occurring less than a year after the July 2009 incident, researchers are rethinking current estimates of the frequency of such planetary impacts on Jupiter.