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Could Asteroid Collision Be Around the Corner?

Jun 05, 12 Could Asteroid Collision Be Around the Corner?

This shows an edge-on view of our solar system. The dots represent a snapshot of the population of NEAs and PHAs that scientists think are likely to exist based on the NEOWISE survey. Positions of a simulated population of PHAs on a typical day are shown in orange, and the simulated NEAs are blue. Earth’s orbit is green.

Image Credit: NASA/JPL-Caltech

An asteroid collision with earth would affect climate negatively for years. It could kill hundreds or thousands more than any earthquake, tornado, tsunami, or nuclear fallout. So many have been cauterized with its ‘end-of-the-world’ effects on us, and with the highly slim chances of its occurrence, that few ever worry—at all.

Attempting to avoid mass panic, NASA is partly to blame for this attitude. Reading ‘in-between’ the lines, they discuss innocuous scientific facts. But what “don’t” they say? The current administration has been negative towards any NASA funding since it’s birth in 1958, and have also decided on prolonged deferral of any future Moon or Mars human landing.

NASA’s Wide-field Infrared Survey Explorer (WISE) has categorized hundreds of millions of objects. NEOWISE (subset of WISE) operates with infrared (or heat) to take pictures of light and dark objects, and hunts asteroids in particular. More specifically, NEOWISE has looked for the Potentially Hazardous Asteroids (PHAs) to earth.

PHAs are large enough to withstand any disintegration through Earth’s atmosphere, and cause catastrophic damage upon impact–larger than any current known effect listed above. They orbit closer than 5 million miles to earth.

From ~300,000 minor planets in our solar system, NEOWISE determined there are ~20,500 Near-Earth Asteroids (NEAs) larger than a football field. But with the more dangerous PHAs, NEOWISE has determined there are approximately 4700 [+/- 1500] with a diameter of at least 330ft.  NEOWISE reveals 20-30% of those PHAs thought to exist, were physically discovered either by telescopic view, or heavenly body perturbation.

If one understands the above statement, they will also realize 70-80% of PHAs have not been physically found yet, but are known to exist. In addition, NEOWISE has found twice as many of the known PHAs to have orbits very close to earth’s. “Our team was surprised to find the overabundance of low-inclination PHAs [close earth orbits],” said Amy Mainzer [NEOWISE Principal Investigator/Jet Propulsion Laboratory].

PHA observation shows they are usually brighter than other asteroids. Brightness indicates composition (i.e., stony or metallic), and what % will make impact. Those compositions will better survive re-entry conditions, and the meteorite will likely impact with more weight and damage.

All these asteroids (min 330ft/d) are large enough to impact with enough energy to have a regional, or continental scale catastrophe. Larger asteroid collisions (> 1 mile/d) would risk mass extinction.

NASA admits many asteroids are discovered only days, or hours, before a close flyby. Of the thousands of known orbiting rogue rocks in our galaxy, many have left their calling card they will be back next year—probably with a little closer orbit.

In Tom’s Asteroid Flybys Webpage, one sees ~fifty of the most very recent flybys. A partial list of PHAs and information on converting absolute magnitudes to diameters is available, as is an explanation of the quantities given in the listings below. A list of close approaches to the earth through the end of the 21st century is available.

The scary part of any close flyby: orbits can be altered by gravitational forces of any object—especially one as large as a planet. NASA is quite good at predicting orbits, times, approach distances, and future possible impacts. Because of unknowns in gravitational attractions of heavenly bodies with orbits in close proximity, exact dates of collisions cannot be predicted.

Recently in 7/2002, 6300ft [2002 NT7], which nearly intersects earth’s orbit, was classified as collision candidate in 2060.

In 08/2002, 2500ft [2002 NY40] approached earth within 330,00 miles.

In 12/2007, 2000ft [2004 XP14] came within 269,000 miles of earth (1.1x earth-moon distance).

In 01/2008, 824ft  [2007 TU24] came within 334,000 miles of earth.

In 11/2011, 1300ft/aircraft-carrier size [2005 YU55} missed earth by only 202,000 miles. Collision candidate in 2022.

In 06/2011, 36ft [2012 BX34] passed within 37,300 miles of earth, with only 2 days warning.

Asteroid 2012 DA14 will pass very close to Earth in 2013 | Space … at a minimum of 12,680 miles. According to Bad Astronomer Phil Plait, even though its orbit has not completely been pinned down, a possible impact in 2020, or later, would be like a thermonuclear bomb. It swings close to earth twice/asteroid-orbit (every 6 mo).

Many PHAs have been named: Ilapa, Castalia, Toutatis, Camillo, Apophis, and Asclepius. All charted and scheduled for revisitation. The most famous—Apophis—will make close encounters in several approaches—the closest in 2029. With its orbital path intersection, its mass and spin pole will likely alter its trajectory and orbit enough for a possible collision in 2036.

As much as 80% of all PHA orbits are not exactly known. Many of the smaller and darker asteroids cannot be spotted until a few days, or even hours, before a known collision.

Asteroid impact response: “not if an impact will occur, but when”.

Interestingly, in the Bible {Matt 25:13}, Christ says: “Therefore, stay awake, for you know neither the day nor the hour.”

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