New Count of Potentially Hazardous Asteroids

A New Count of Potentially Hazardous Asteroids

May 16, 2012:  Observations from NASA's Wide-field Infrared Survey Explorer (WISE) have led to the best assessment yet of our solar system's population of potentially hazardous asteroids. Also known as "PHAs," these asteroids have orbits that come within five million miles (about eight million kilometers) of Earth, and they are big enough to survive passing through Earth's atmosphere and cause damage on a regional, or greater, scale.

The asteroid-hunting portion of the WISE mission, called NEOWISE, sampled 107 PHAs to make predictions about the population as a whole. Findings indicate there are roughly 4,700 PHAs, plus or minus 1,500, with diameters larger than 330 feet (about 100 meters). So far, an estimated 20 to 30 percent of these objects have been found.

In this simulated view of the near-Earth asteroid population, potentially hazardous asteroids (PHAs) are denoted in orange. Less dangerous near-Earth asteroids are blue. Earth's orbit is green. [more]

While previous estimates of PHAs predicted similar numbers, they were rough approximations. NEOWISE has generated a more credible estimate of the objects' total numbers and sizes. Because the WISE space telescope detected the infrared light, or heat, of asteroids, it was able to pick up both light and dark objects, resulting in a more representative look at the entire population.

"The NEOWISE analysis shows us we've made a good start at finding those objects that truly represent an impact hazard to Earth," said Lindley Johnson, program executive for the Near-Earth Object Observation Program at NASA Headquarters. "But we've many more to find, and it will take a concerted effort during the next couple of decades to find all of them that could do serious damage or be a mission destination in the future."

This orbit diagram illustrates the difference between a PHA and less hazardous near-Earth asteroids (NEA). [more]

The new analysis suggests that about twice as many PHAs as previously thought reside in low-inclination orbits, which are roughly aligned with the plane of Earth's orbit.

"Our team was surprised to find the overabundance of low-inclination PHAs," said Amy Mainzer, NEOWISE principal investigator, at NASA's Jet Propulsion Laboratory. "Because they will tend to make more close approaches to Earth, these targets can provide the best opportunities for the next generation of human and robotic exploration."

The NEOWISE analysis suggests a possible origin for the low-inclinaton PHAs: Many of them could have originated from a collision between two asteroids in the main belt lying between Mars and Jupiter. A larger body with a low-inclination orbit may have broken up in the main belt, causing some of the fragments to drift into orbits closer to Earth and eventually become PHAs.

The lower-inclination PHAs appear to be somewhat brighter and smaller than other near-Earth asteroids. The discovery that PHAs tend to be bright says something about their composition; they are more likely to be either stony, like granite, or metallic. This type of information is important in assessing the space rocks' potential hazards to Earth. The composition of the bodies would affect how quickly they might burn up in our atmosphere if an encounter were to take place.

"The NEOWISE project, which wasn't originally planned as part of WISE, has turned out to be a huge bonus," said Mainzer.  "Everything we can learn about these objects helps us understand their origins and fate."

The NEOWISE results have been accepted for publication in the Astrophysical Journal.

SOURCE: http://science.nasa.gov/science-news/science-at-nasa/2012/16may_pha/

On May 17, 2012 there were 1287 potentially hazardous asteroids.

Recent & Upcoming Earth-asteroid encounters:

Asteroid	Date(UT)	Miss Distance	Mag.	Size
2012 JU	May 13	0.5 LD	--	10 m
2012 KA	May 17	0.6 LD	--	8 m
2010 KK37	May 19	2.3 LD	--	31 m
4183 Cuno	May 20	47.4 LD	--	5.7 km
2012 JV11	May 22	6.7 LD	--	69 m
2002 VX94	May 26	72.8 LD	--	1.1 km
2002 AC	Jun 16	62.2 LD	--	1.2 km
1999 BJ8	Jun 16	68.8 LD	--	1.1 km
2005 GO21	Jun 21	17.1 LD	--	2.2 km
2003 KU2	Jul 15	40.3 LD	--	1.3 km
2004 EW9	Jul 16	46.8 LD	--	2.1 km
2002 AM31	Jul 22	13.7 LD	--	1.0 km
37655 Illapa	Aug 12	37 LD	--	1.2 km

Notes: LD means "Lunar Distance." 1 LD = 384,401 km, the distance between Earth and the Moon. 1 LD also equals 0.00256 AU. MAG is the visual magnitude of the asteroid on the date of closest approach.
SOURCE:http://spaceweather.com/

Space Junk Danger To Sunken Ocean Treasure.

Space Junk: danger of floating debris

Reported by: Emily Clark

SALT LAKE CITY (ABC 4 News) – The sky might not be falling, but a lot of space junk is. This traffic jam in outer space could interfere with parts of your daily life.

16,000 pieces of space junk are out there, moving at 17,000 miles an hour.

Seth Jarvis at Clark Planetarium put it into perspective, he said “A grain of rice at this speed is the equivalent of a guy my size crashing into you on a motorcycle

That’s a grain of rice, imagine something bigger.

Jarvis said, “It's like setting off a bomb if it hits something.”

There are all sizes of space junk out there; made by nature and man. While this might seem like just a mess, it’s a real problem. It’s not as much a worry of junk falling to the earth, although that has happened, but the real problem is collisions.

Jarvis said, “What if that satellite smacks into a stray bolt?”

If there is a collision with a satellite for your cell phone, internet, TV – we would have serious issues.

read more at ABC4.com

Modern treasure hunters claim they've found billions in sunken ship off Boston

By Molly Line

Published February 08, 2012

| FoxNews.com

Modern-day treasure hunters say they've found a sunken ship off the coast of Cape Cod, Mass., holding one of the biggest fortunes ever discovered in the ocean depths.

"There's 71 tons of platinum, there's some gold ingots and there's also some uncut diamonds, industrial diamonds, that were on the Port Nicholson," said Capt. Gary Esper. He's one member of the team hoping to bring the goods to the surface. "I like to call us explorers rather than treasure hunters because treasure hunters have a bad name these days so we just went out there looking for the ship," said Esper.

It was no easy task for Sub Sea Research, co-owned by Greg Brooks, based out of Portland, Maine.

"It was extremely difficult. We spend almost three months looking for it," said Brooks.

"A few days before I almost pulled the plug."

The discovery was made in 2008, but the crew kept quiet while resources and initial legal rights were secured.

The S.S. Port Nicholson was torpedoed by a German U-boat in 1942 during World War II. According to Esper, research shows the vessel drifted before finally sinking, plunging 700 feet into the depths of Georges Bank, a popular fishing channel littered with shipwrecks and known for strong currents and turbulent weather.

The British merchant vessel's cargo, a payment of precious metals from Russia to the United States, is estimated to be worth $3 billion, but bringing the find to the surface won't be easy.

"Difficult. Very difficult. The pressure is immense down there. It is diveable, but it's a very scary dive," said Esper.

Instead, the team will use a remotely operated vehicle, a submersible robot with a claw, to grab its find and bring it up into the light.

The search has already cost millions of dollars. Wealthy investors are hoping for a big payday, but there is no guarantee.

Maritime law is complicated. Britain has yet to decide whether or not to file a claim on the cargo, waiting for the salvage operation to begin, and with so much money at stake legal experts expect a battle likely involving multiple parties.

Read more: FoxNews