Dino-killing asteroid traced back 160m years

[Rick]

The dinosaur-busting asteroid that slammed into Earth some 65 million years ago has been traced back to a collision between two monster chunks of rock 160 million years ago, out in the main asteroid belt.

According to researchers at the Southwest research Institute (SwRI) and the University of Prague, the dino-killer most likely began its journey to Earth before T-Rex had even evolved, when a relatively small (60 kilometres) asteroid crashed into a much bigger 170 kilometre monster rock.

More: http://www.theregister.co.uk/2007/09/06/dino_killer/

(So when's that movie coming  out, I wonder...)

[Rick]

A colossal collision in space 160 million years ago set the dinosaurs on the path to extinction, a study claims. An asteroid pile-up sent debris swirling around the Solar System, including a chunk that later smashed into Earth wiping out the great beasts.

Other fragments crashed into the Moon, Venus and Mars, gouging out some of their most dominant impact craters, a US-Czech research team believes.

More: http://news.bbc.co.uk/2/hi/science/nature/6980468.stm

[Rick]

Russian Meteorite Sheds Light on Dinosaur Extinction Mystery

A long-standing debate about the source of the asteroid that impacted the Earth and caused the extinction of the dinosaurs has been put to rest thanks to the Chelyabinsk meteorite that disintegrated over Russia in February 2013, a new paper published in the journal Icarus shows.

Astronomers have debated whether the dinosaur killer was linked to the breakup of a large asteroid forming the Baptistina Asteroid Family (BAF) beyond Mars, some of which ended up on Earth-crossing orbits. The asteroid impacting Earth is thought to have been dark and carbonaceous. The BAF hypothesis was bolstered by them being dark and with a spectral shape similar to carbonaceous meteorites.

Analysis of the Chelyabinsk meteorite shows that shock produced during catastrophic disruption of a large asteroid can darken otherwise bright silicate material. Shock darkening was first reported by Dan Britt (now at the University of Central Florida) in the early 1990s. The Chelyabinsk meteorite has both bright unshocked and dark shocked material. However, the details of the spectra of the dark Chelyabinsk material closely reproduces spectral signatures seen with members of the Baptistina Asteroid Family, said Planetary Science Institute Research Scientist Vishnu Reddy, lead author of  "Chelyabinsk meteorite explains unusual spectral properties of Baptistina Asteroid Family" that appears in Icarus.

More: http://www.psi.edu/news/press-releases (July 16, 2014)

[Rick]

Doubt cast on global firestorm generated by dino-killing asteroid

Pioneering new research has debunked the theory that the asteroid that is thought to have led to the extinction of dinosaurs also caused vast global firestorms that ravaged planet Earth.

A team of researchers from the University of Exeter, University of Edinburgh and Imperial College London recreated the immense energy released from an extra-terrestrial collision with Earth that occurred around the time that dinosaurs became extinct. They found that the intense but short-lived heat near the impact site could not have ignited live plants, challenging the idea that the impact led to global firestorms.

These firestorms have previously been considered a major contender in the puzzle to find out what caused the mass extinction of life on Earth 65 million years ago.

The researchers found that close to the impact site, a 200 km wide crater in Mexico, the heat pulse - that would have lasted for less than a minute - was too short to ignite live plant material. However they discovered that the effects of the impact would have been felt as far away as New Zealand where the heat would have been less intense but longer lasting - heating the ground for about seven minutes - long enough to ignite live plant matter.

More: http://www.exeter.ac.uk/news/featurednews/title_430274_en.html