Asteroid Capture!

Russia Meteorite 2013: The largest of the century!

Russia Meteorite 2013: The largest of the century!

Asteroids are an excellent source of natural resources (minerals, etc.) As stated in the U.S. fiscal year of 2014 budget, NASA requested $100 million to initiate plans to capture an asteroid, haul it into the lunar orbit, and send manned missions to the asteroid by 2025! Mining an asteroid in the future could help resupply rapidly depleting fossil fuels and natural minerals. Beside the apparent need for resources, NASA hopes to advance technological developments that will provide opportunities for “international cooperation, new industrial capabilities, and helping scientists better understand how to protect Earth if a large asteroid is every found on a collision course. You may have heard about the recent Russia Chelyabinsk meteorite incident. 1,500 injured and 7,000 buildings suffered. A small asteroid invaded Earth’s atmosphere and struck the ground in Russia. The shockwaves shattered thousands of windows!

NASA proposes identifying suitable targets, or asteroids 20 to 30 feet in diameter (extremely hard to spot) in favorable orbits (near Earth and small revolution) that would allow easy capture and transport to Earth. These desired small asteroids hit Earth on a regular basis; the asteroid that hit Russia was 50 feet in diameter. NASA’s Orion crew capsule and heavy-lift booster will send astronauts to the asteroid for sample returns. NASA has two teams working the proposed mission: one searching for suitable asteroids and developing unmanned technology to capture the asteroid, and another on future manned missions and sample collection.

In the wake of the asteroid (then meteorite) rocking Russia and a close call with an asteroid passing close to Earth on the same day, astronomers are extremely interested in asteroids.

Proposed Timeline

2017: test flight

2019: capture mission

2021: asteroid hauled back to cislunar (between Earth and moon) orbit

by 2025: astronauts sent to asteroid

References:

Harwood, William. “NASA mulls asteroid capture mission, eventual manned visits.” CBS News. CBS News, 5 Apr 2013. Web. 12 Apr 2013.

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Meteroite Dating

How do scientists determine the age of meteorites, most of which are around 4.5 billion years old. –Amy

Meteorite

Meteorite Dating

Scientists measure the age of meteorites with the decay of radioactive isotopes. What is an isotope? Isotopes are elements with the same number of protons but a different number of neutrons. For instance, carbon-12 has 6 neutrons and carbon-14 has 8 neutrons. Some isotopes are very unstable and tend to decay into lighter elements by alpha or beta particle decay. Scientists use the half-life of certain elements to date objects. First, scientists must determine to isotope to use by examining the elemental composition of the object. For meteorites, scientists generally use Rubidium-87/ Strontium-87 decay, which has a half-life of 49 billion years. Rubidium-87 decays into Strontium-87. So if the object has 50% Rubidium-87 and 50% Strontium-87  (only formed by decay process), then the object is 49 million years old. Since some Strontium-87 may have been present originally, scientists use Strontium-86, whose content remains the same, as a reference. Determining the ratio between Rubidium-87/ Strontium-86 and Strontium-87/ Strontium-86 via mass spectrometer (vaporizes a tiny portion of the meteorite to form ions; the ions are then separated by mass in a magnetic field), scientists can then calculate the amount of each isotope present in the meteorite, and thus the age of meteorites. Although radioactive dating is the best method for scientists to date meteorites, many factors, such as the amount of sunshine or heavy rain, can affect measurements.