It’s time to dip into the “space” file, and today we’re going to talk about a very familiar object: dust. It turns out that not only is dust common in your living room, it’s very common in the universe. But perhaps not everywhere.
Four years ago, a student-built University of Colorado Boulder instrument riding on NASA’s New Horizons spacecraft found only a handful of dust grains, the building blocks of planets, when it whipped by Pluto at 31,000 mph.
The dust counter is a thin film resting on a honeycombed aluminum structure the size of a cake pan mounted on the spacecraft’s exterior. A small electronic box records each individual dust particle that strikes the detector, allowing the students to infer the mass of each particle.
Data downloaded and analyzed by the New Horizons team indicated the space environment around Pluto and its moons contained only about six dust particles per cubic mile. This means that, at least in the region of Pluto, space is mostly empty. Any debris created when Pluto’s moons were captured or created during impacts has long since been removed by planetary processes.
Ultima Thule asteroid is a little smaller than Guam and 4 billion miles away
Launched in 2006, the New Horizons mission was designed to help planetary scientists better understand the icy worlds at the edge of our solar system, including Pluto and the Kuiper Belt.
And New Horizons is still doing science. Earlier this year it whizzed by a very strange world called Ultima Thule. This asteroid is a little smaller than Guam and it’s a contact binary which means it’s made from two rocks stuck together, one large and one smaller. It actually looks rather like a snowman.
The New Horizon scientists think that the two rocks collided gently, but data are still being returned. New Horizons is nearly 4.13 billion miles from Earth and at that distance, radio signals, traveling at light speed, reach the large antennas of NASA’s Deep Space Network six hours and nine minutes after New Horizons sends them.
But to return to our original dusty topic, researchers from the University of Edinburgh have proposed the theory that life on our planet might have originated from biological particles brought to Earth in streams of space dust.
162,000 mph rivers of space dust could carry life between planets
The researchers calculated how powerful flows of space dust, which can move at up to 45 miles a second, could collide with particles in our upper atmosphere. It found that small particles existing at 100 miles or higher above Earth’s surface could be knocked beyond the limit of Earth’s gravity by space dust and eventually reach other planets. The same mechanism could enable the exchange of atmospheric particles between planets.
And in a nod to last week’s Post column, the researchers say that some bacteria, plants and small animals called tardigrades are known to be able to survive in space, so it is possible that if such organisms were present in Earth’s upper
atmosphere they might collide with fast-moving space dust and withstand a journey to another planet.
So, the next time you whip out the dust rag, remember that dust could be pretty important!