Earth’s gravity may lure deadly asteroid

A HUGE asteroid which is on a course to miss the Earth by a whisker in 2029 could go round its orbit again and score a direct hit a few years later.

Astronomers have calculated that the 1,000ft-wide asteroid called 2004 MN4 will pass by the Earth at a distance of between 15,000 and 25,000 miles — about a tenth of the distance between the Earth and the Moon and close enough to be seen with the naked eye.

Although they are sure that it will miss us, they are worried about the disturbance that such a close pass will give to the asteroid’s orbit. It might put 2004 MN4 on course for a collision in 2034 or a year or two later: the unpredictability of its behaviour means that the danger might not become apparent until it is too late.

As a safety precaution, some experts are calling for 2004 MN4 to be “tagged” with a transponder that would constantly radio its position. Scientists hope that this would provide enough warning to allow emergency action if necessary, possibly by diverting the object away from the Earth.Other instruments on the probe could provide information about its composition.

Benny Peiser, from Liverpool John Moores University, who is an expert on asteroid hazards, said: “We don’t know what that asteroid is made of and that might influence the way it’s affected by the Earth’s gravitational pull. There are other close approaches, in 2034 and 2035. In all likelihood it will produce an orbit that will not intercept the Earth, but we don’t know.”

The asteroid is big enough to cause damage on a regional scale, with an expected impact equivalent to a 1,000-megatonne explosion. It was discovered last June and its orbit plotted in detail by December. Startled astronomers calculated at one point that its chances of a direct hit on Friday, April 13, 2029, were 1 in 38. But additional calculations have set those fears to rest. The asteroid is now expected to miss but come close enough to be below the altitude of TV satellites. It should be visible as a rapidly moving point of light.

Brian Marsden, of the Harvard-Smithsonian Centre for Astrophysics in Cambridge, Massachusetts, expects the close encounter to increase the frequency of the asteroid’s orbit, creating the possibility of further close encounters every five to nine years.

An interceptor mission is feasible and Dr Peiser said that an opportunity would arise in 2012, when 2004 MN4 will be ten million miles from Earth. “That’s not a big distance as far as space missions go,” he said.

“This is most likely not the object with our number on it, but one day we will have to address this question and we’ll need the technology. A transponder mission should not be too complicated or costly, and would provide a lot of vital data.”

> I thought the prophecy was that the one being selected now will be the last one.

Not quite:
http://www.catholic-pages.com/grabbag/malachy.asp

266 John Paul II (1978-2005) 110 De labore Solis
(of the eclipse of the sun, or from the labour of the sun)
Hist.: Karol Wojtyla was born on May 18, 1920 during a solar eclipse. He also comes from behind the former Iron Curtain (the East, where the Sun rises). He might also be seen to be the fruit of the intercession of the Woman Clothed with the Sun labouring in Revelation 12 (because of his devotion to the Virgin Mary). His Funeral occurred on 8 April, 2005 when there was a solar eclipse visible in the Americas.
267 ??? 111 Gloria olivæ
The Benedictine order traditionally said this Pope would come from their order.
268 ??? In persecutione extrema S.R.E. sedebit Petrus Romanus, qui pascet oves in multis tribulationibus: quibus transactis civitas septicollis diruetur, & Judex tremêdus judicabit populum suum. Finis.
(In extreme persecution, the seat of the Holy Roman Church will be occupied by Peter the Roman, who will feed the sheep through many tribulations, at the term of which the city of seven hills will be destroyed, and the formidable Judge will judge his people. The End.)

Formatting issues. See the site.

Gravity is a function of mass, and SUV's have mass, therefore if we ban SUV's we're safe, right?

If your theory holds true, then all we need to do is get all the fat people to loose some wieght. That will reduce gravity and therefore have less effect on this space rock. Or, we can build a huge rocket engine on earth, and just blast ourselves out of the way. That might be a better solution because there are bound to be more of them comming. It's really unfortunate that I'll probably be dead by then and miss all the panic. I see how stupid people are getting now after being "educated" in our school system. Imagine how dumb they will be by the time this rock hits us. Maybe they will have forgotten all about it by then, who knows. We can be sure that they will have fogotten how to do the math to figure out if it will hit or not.

>> Why hasn't Jupiter gobbled this one up yet?

> Because the asteroids orbit goes nowhere near Jupiter.

There is nothing about the existance of this asteriod that is inconsistent with current models of the age of the Solar System.

Chunks of rock get kicked out of the asteriod belt every now and then. This one is has only been in its current orbis for a some millions of years. Evenutally it will hit Earth or fall into resonance with Venus, or Earth.

You can go here to visualize its orbit:

http://neo.jpl.nasa.gov/cgi-bin/db_shm?des=2004%20MN4

You can pan, zoom, enter dates and let it spin. Apparently the visualization only does Keplerian orbits, they do not account for "secular [non cyclical] effects".

using
http://www.lpl.arizona.edu/impacteffects/

Your Inputs:
Distance from Impact: 100.00 km = 62.10 miles
Projectile Diameter: 1000.00 m = 3280.00 ft = 0.62 miles
Projectile Density: 8000 kg/m3
Impact Velocity: 17.00 km/s = 10.56 miles/s
Impact Angle: 30 degrees
Target Density: 2750 kg/m3
Target Type: Crystalline Rock

Energy:
Energy before atmospheric entry: 6.05 x 1020 Joules = 1.45 x 105 MegaTons TNT
The average interval between impacts of this size somewhere on Earth during the last 4 billion years is 1.0 x 106years

Atmospheric Entry:
The projectile begins to breakup at an altitude of 14200 meters = 46500 ft
The projectile reaches the ground in a broken condition. The mass of projectile strikes the surface at velocity 16.9 km/s = 10.5 miles/s
The impact energy is 6.02 x 1020 Joules = 1.44 x 105MegaTons.
The broken projectile fragments strike the ground in an ellipse of dimension 2.09 km by 1.04 km

Major Global Changes:
The Earth is not strongly disturbed by the impact and loses negligible mass.
The impact does not make a noticeable change in the Earth's rotation period or the tilt of its axis.
The impact does not shift the Earth's orbit noticeably.

Crater Dimensions:
What does this mean?
Crater shape is normal in spite of atmospheric crushing; fragments are not significantly dispersed.

Transient Crater Diameter: 12.6 km = 7.85 miles
Transient Crater Depth: 4.47 km = 2.78 miles

Final Crater Diameter: 17.7 km = 11 miles
Final Crater Depth: 0.703 km = 0.436 miles

The crater formed is a complex crater.
The vol of the target melted/vaporized is 2.68 km3=0.642 mi3
Roughly half the melt remains in the crater , where its average thickness is 21.3 meters = 69.9 feet

Thermal Radiation:
Time for maximum radiation: 0.996 seconds after impact

Visible fireball radius: 16.1 km = 10 miles
The fireball appears 36.6 times larger than the sun
Thermal Exposure: 2.70 x 107 Joules/m2
Duration of Irradiation: 219 seconds
Radiant flux (relative to the sun): 123

Effects of Thermal Radiation:
Clothing ignites
Much of the body suffers third degree burns
Newspaper ignites
Plywood flames
Deciduous trees ignite
Grass ignites

Seismic Effects:
The major seismic shaking will arrive at approx 20 seconds.
Richter Scale Magnitude: 8.1
Mercalli Scale Intensity at a distance of 100 km:

VII. Damage negligible in buildings of good design and construction; slight to moderate in well-built ordinary structures; considerable damage in poorly built or badly designed structures; some chimneys broken.

VIII. Damage slight in specially designed structures; considerable damage in ordinary substantial buildings with partial collapse. Damage great in poorly built structures. Fall of chimneys, factory stacks, columns, monuments, walls. Heavy furniture overturned.

Ejecta:
The ejecta will arrive approx 144 seconds after the impact.
Average Ejecta Thickness: 22.8 cm = 8.99 inches
Mean Fragment Diameter: 11.4 cm = 4.47 inches

Air Blast:
The air blast will arrive at approximately 303 seconds.
Peak Overpressure: 176000 Pa = 1.76 bars = 24.9 psi
Max wind velocity: 262 m/s = 585 mph
Sound Intensity: 105 dB (May cause ear pain)
Damage Description:
Multistory wall-bearing buildings will collapse.
Wood frame buildings will almost completely collapse.
Highway truss bridges will collapse.
Glass windows will shatter.
Up to 90 percent of trees blown down; remainder stripped of branches and leaves.

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