Jan 25

Space Junk Menace: How to Deal with Orbital Debris

by Leonard  David, SPACE.com’s Space Insider Columnist

The saga of what steps that must be taken to deal with the evolving threat of Earth-circling orbital debris is a work in progress.  This menacing problem — and the possible cleanup solutions — is international in scope.

Space junk is an assortment of objects in Earth orbit that is a mix of everything from spent rocket stages, derelict satellites, chunks of busted up spacecraft to paint chips, springs and bolts. A satellite crash in February 2009, for example, marked the first accidental hypervelocity crash between two intact artificial satellites in Earth orbit. That cosmic crash created significant debris — a worrisome amount of leftover bits and pieces.

Against this backdrop of untidiness in space and the global worry among spacefaring countries it causes, experts continue to tackle the issue of exactly what to do about orbital debris. A number of rules have been pondered to address the space debris problem, from regulations that attempt to cut down on the shedding of new debris to better tracking of the human-made refuge, as well as scavenging concepts including fishing nets, lasers and garbage scows.

But how to best characterize the orbital debris dilemma, and its future, also stirs up debate and heated dialogue.

 

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Jan 24

Dung Beetles Follow the Stars

By Katherine Harmon

dung beetle milky way stars orient straight path

Dung beetle on dung ball under the Milky Way; image courtesy of Emily Baird

The humble dung beetle makes its living rolling big balls of excrement to feed its offspring and itself. But this lowly occupation doesn’t mean the insect doesn’t have its eye on the skies—even when the sun goes down.

Recent research has shown that African ball-rolling dung beetles (Scarabaeus satyrus) use strong light cues from the sun and moon to keep traveling in a straight path. But researchers observing these beetles noticed something curious. “Even on clear, moonless nights, many dung beetles still manage to orientate along straight paths,” Marie Dacke, of Lund University in Sweden, said in a prepared statement. What else could the animals be using for guidance? The stars, of course.

“We were sitting out in Vryburg [in South Africa] and the Milky Way was this massive light source,” said Marcus Byrne, of Wits University and co-author on the new study, in a prepared statement. “We thought, they have to be able to use this—they just have to!” Their findings were published online January 24 in Current Biology.

Humans, of course, have long used stars for navigation. And some bird and seal species are thought to do so as well. The use of the Milky Way in particular has been suggested for some insects, spiders and vertebrates, but it has yet to be shown quite as convincingly as the researchers were able to demonstrate for these beetles, which have also recently been shown to engage in complex “dances” to orient themselves on top of their excrement orbs.

dung beetle milky way stars cap

Dung beetle in experimental cardboard cap to block view of stars; image courtesy of Marcus Byrne

To see if the starry sky was really serving as such a lofty guide for these little bugs, researchers designed specially crafted cardboard caps for their subjects.

On a starry, moonless evening, researchers released capped-beetles with their dung balls from a central spot. The area was a flat sandy surface surrounded by a one-meter high, circular wall. As a test, other beetles were left uncapped and a third group received transparent plastic caps. The cap-less beetles and those with clear caps had standard, relatively straight paths. But those with the obstructed views meandered far afield and had much longer, inefficient trails.

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Jan 24

Mystery of Strange Star Outbursts May Be Solved

by Charles Q.  Choi, SPACE.com Contributor

 

Scientists have detected what appears to be a stellar outburst from a pair of stars locked in a cosmic tryst within a shared veil of gas, a find that marks the first discovery of a long-sought type of space eruption.

Most outbursts from stars are lumped into two categories — novas or supernovas. A nova is a thermonuclear explosion from a white dwarfstar driven by fuel piled on from a companion star. Novas do not result in the destruction of their stars, but supernovas do.

Supernovas, which are bright enough to briefly outshine all the stars in their galaxies, happen in two known ways — type Ia supernovas occur after a white dwarf dies from gorging on too much fuel from a companion star, while type II supernovas take place after the core of a star runs out of fuel, collapses into an extraordinarily dense nugget in a fraction of a second, and then bounces and blasts outward.

However, over the years, scientists have recognized another class of outbursts that are brighter than novas but dimmer than supernovas. Investigators called these mysterious events intermediate-luminosity red transients, or ILRTs. [Top 10 Star Mysteries]

Now, researchers suggest the culprits behind these enigmas may lurk behind shrouds of gas.

“I find it extremely exciting that we have explained a class of events that previously no one knew what they were,” study lead author Natasha Ivanova, an astrophysicist at the University of Alberta in Canada, told SPACE.com. “That does not happen very often in science.”

 

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