Aim is to see whether space rocks can be deflected should one threaten humans with same fate as dinosaurs
Most mission scientists would wince at the
thought of their spacecraft being smashed to smithereens. But for those
behind Nasa’s Dart probe, anything short of total destruction will be
chalked up as a failure.
The $330m (£300m)
spacecraft is due to slam head-on into an asteroid about 11m kilometres
above the Indian Ocean soon after midnight on Monday. The impact, at
nearly seven kilometres a second, will obliterate the half-tonne probe,
all in the name of planetary defence.
Not
that Dimorphos, the asteroid in question, poses any threat to humanity.
The Dart, or double asteroid redirection test, is an experiment, the
first mission ever to assess whether asteroids can be deflected should
one ever be found on a collision course with Earth. A well-placed nudge
could avert Armageddon, or so the thinking goes, and spare humans the
same fate as the dinosaurs. …
The Fermi bubbles are massive structures extending from the Milky Way, reaching 50,000 light-years in length.
Mysterious ultrabright gamma-ray emissions in the giant bubbles blown out by our galaxy may finally have an explanation.
Researchers used data from the Gaia and Fermi
space telescopes to search through the Fermi bubbles, a pair of
colossal hourglass-shaped bubbles that extend from the poles of the Milky Way and span 50,000 light-years, to trace the source of the very bright gamma-ray emission spots.
They
discovered that one of the brightest of these spots, dubbed the “Fermi
cocoon,” located in the southern bubble, was caused by emissions from
rapidly spinning dead stars called pulsars in the Milky Way’s satellite galaxy Sagittarius.
The finding could shed light on how these collapsed dead stars act as
cosmic particle accelerators, blasting out high-energy particles that go
on to cause gamma-ray emissions. …
