Thanks to data from NASA’s Spitzer Space Telescope, scientists are finding out that asteroids somewhat near Earth – termed Near-Earth Objects, or NEOs – come in all sorts of colors and compositions.
Getting to know these space rocks is a step closer in dispatching robotic and human missions in the future.
The Spitzer observations of 100 known NEOs have shown that their diversity is greater than previously thought – a rich assortment of colors and compositions.
“These rocks are teaching us about the places they come from,” said David Trilling, assistant professor of physics and astronomy at Northern Arizona University. He is lead author of a new paper on the research appearing in the September issue of the Astronomical Journal.
“It’s like studying pebbles in a streambed to learn about the mountains they tumbled down,” Trilling noted.
Trilling and his team have analyzed preliminary data on 100 NEO asteroids so far. They plan to observe 600 more over the next year. There are roughly 7,000 known near-Earth objects out of a population expected to number in the tens to hundreds of thousands.
As that population grows, a new generation of 21st century spacecraft missions can be planned. Furthermore, that growing catalog of NEOs will support the plotting out of a human sojourn to selected bodies.
Solar system soup
The new data show that some of the smaller objects have surprisingly high albedos – that’s a measurement of how much sunlight an object reflects. Since asteroid surfaces become darker with time due to exposure to solar radiation, the presence of lighter, shinier surfaces for some asteroids may indicate that they are relatively young. This is evidence for the continuing evolution of the near-Earth object population.
Also, the asteroids observed so far have a greater degree of diversity than expected – an indication that they might have different origins.
For example, some asteroids may come from the main belt between Mars and Jupiter. Others could come from farther out in the solar system. This diversity also suggests that the materials that went into creating the asteroids — the same stuff that make up our planets — were probably mixed together like a big solar-system soup very early on in its history.
The Spitzer data complements that of NASA’s Wide-field Infrared Survey Explorer, or WISE, an all-sky infrared survey mission up in space now. It too has been busy observing more than 430 near-Earth objects. Of these, more than 110 are newly discovered.
In the future, both Spitzer and WISE will reveal even more about the “flavors” of near-Earth objects.
This bounty of information from space-based telescopes could reveal new clues about how the cosmic objects might have dotted our young planet with water and organics – ingredients needed to jump-start life.
By LD/CSE