- Our space exploration is just beginning to learn about the near-Earth asteroids. There are millions of them that orbit with us around the Sun. Maybe we should begin tracking their trajectories and predicting any collisions. Then what?
- Attachments : picture
- There are 5 Lagrangian Points around the Earth. The points L4 and L5 lie just 60 degrees ahead and 60 degrees behind the Earth. Asteroid “2010TK” is trapped in Lagrangian Point L4, 60 degrees ahead in Earth’s orbit around the Sun.
- This asteroid is about 1,000 feet in diameter and some 50,000,000 miles away. It is very dim at 20.6 Magnitude brightness. Its reflectivity is 10%. Also called ‘albedo’, the Moon’s reflectivity is 7%. The asteroid does not stay exactly at the Lagrangian Point but oscillates in a tad-pole shaped loop that it traverses every 365 years. The closest point it reaches to Earth is 12,400,000 miles.
- This asteroid is not economical for us to visit because it orbit inclines by 21 degrees to our plane of orbit. This would require the rocket spacecraft to have a velocity of 21,000 miles per hour to reach it. There are other near-Earth asteroids that can be reached with rocket velocities of only 9,000 miles per hour.
- We have visited another asteroid named 21 Lutetia. The Rosetta spacecraft passed within 1,965 miles of Lutetia in July, 2010. The “ Dawn” spacecraft visited 4 Vesta asteroid that same month.
- Lutetia is a piece of planetisimals that was around during the formation of the planets some 5 billion years ago. It orbits the Sun at 2.4 Astronomical Units which puts it at the near-side of the Asteroid Belt between Mars and Jupiter. It takes 3.8 years to complete one orbit.
- Lutetia is odd shaped 75 miles by 62 miles by 46 miles dimensions. Its composition is “enstatite chondrite”, which is pretty uncommon and thought to be the starting composition of the terrestrial planets. Its surface is loosely aggregated dust particles 50 to 100 micrometers in size. Its density is 3.4 grams per cubic centimeter. ( water is 1.0). This heavier density tells astronomers that the rocky body probably maintained its primordial state.
- Lutetia’s surface has 350 impact craters ranging in diameter from 600 to 55,000 meters.
Its surface is intersected by fractures, scarps, and grooves that are thought to be caused by internal fractures. This asteroid has likely survived intact from the beginning of the Solar System. Astronomers expect it to have a metallic core, a mantel, and a surface crust that has never melted. They think it formed some 3,000,000 years of the formation of the Solar System. It sure would be fun to learn some more about this particular asteroid.
- Who is watching these asteroids to learn if one is about to collide with the Earth?
- No one really!
- Yet, we can record over 1,000,000 asteroids over 40 meters in diameter orbiting in our vicinity as we orbit the Sun. One of these asteroids struck the Earth in 1908 over the Siberia in Russia. Its devastation to that unlucky wasteland was 150 time larger than the destruction power of the Hiroshima atomic bomb.
- Who is going to find, track, and predict the trajectories of all of these asteroids? It seems that is a national priority that ought to be funded. Some astronomers have tracked all those asteroids they could find over 1,000 meters in diameter. Their calculated that these trajectories are not expected to hit us over the next 100 years. However, thousands of smaller asteroids remain on the loose. Anyone could be big enough to destroy a country if it hit land. An asteroid hitting the oceans could create a tsunami wave that would devastate all its coastal cities.
- We have the infrared telescopes that could detect these asteroids but there is no funding for such a project. We need the leadership in Washington that is not worrying about this years election, rather, worrying about how to protect our planet for the next generation, both economically and physically. We need to fund projects now that experiment with what to do after we find an asteroid heading our way. It would be a dumb idea to just blow it up because it would just change the impact from a bullet wound to a shotgun blast. We need to experiment with a ‘controlled way’ to move an asteroid off its trajectory.
- Can we learn how to deflect an asteroid. The dinosaurs did not fund such a project and look what happened to them. The evolution of the Solar System is still happening. Do we participate or just let nature take its course? An announcement will be made shortly, stay tuned.
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707-536-3272, Friday, January 13, 2012
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