Sky Watchers' Association: 2012

Saturday 10 November 2012

A Special Talk

Dr. Dipankar Maitra

A special “very informal” talk by

Dr. Dipankar Maitra, University of Michigan,

Ann Arbor,Michigan.

Subject:

Measuring how fast black holes spin.

Date, time and place:

24 November 2012, 6:00 pm at Sky Watchers’ Association, Dhakuria

Sunday 2 September 2012

Wednesday 20 June 2012

Asteroid 2012 DA14 will be seen on February 15, 2013

About

2012 DA14 is a near earth asteroid with an estimated diameter of about 44 meters and an estimated mass of about 120,000 metric tons.^[1] It was discovered on February 23, 2012, by the OAM Observatory, La Sagra in Spain (J75). Calculations show that on February 15, 2013, the distance between the asteroid and the Earth will be 0.09 LD (35,000 km; 21,000 mi).

Risks

As of May 1, 2012, the odds of impact on 2020-Feb-16 are 1 in 37,037,000.^[1]
There is an estimated cumulative 0.031% risk (1 in 3,230) of 2012 DA14 impacting Earth sometime between 2020 and 2082.^[1]
It is rated a low −3.19 on the Palermo Scale.^[5] (The risk is less than one thousandth of the estimated risk of another similarly sized near earth asteroid hitting the Earth during that time period.^[6] It is estimated that there are more than a million near-Earth asteroids smaller than 100 meters.)^[7]
It rates 0 (No Hazard) on the Torino scale.^[1]

If it were to strike the Earth, it is estimated that it would produce the equivalent of 2.4 megatons of TNT.^[1] The Tunguska event has been estimated at 3−20 megatons.^[8]

On February 15, 2013, DA14 will pass no closer than 0.000181 AU (27,100 km; 16,800 mi) from the center-point of the Earth,^[9] which is no closer to the Earth's surface than 3.2 Earth radii.^[4] Thenominal pass will be 0.00023 AU (34,000 km; 21,000 mi) from the center-point of the Earth.^[9] This is potentially closer than satellites in geosynchronous orbit. The asteroid will not be visible to the naked eye.^[4] Due to the uncertainty in the observation arc of 79 days, there is a small possibility that the asteroid will pass 0.00035 AU (52,000 km; 33,000 mi) from the Earth on February 15, 2013.