Sentences with phrase «by big asteroids»

The authors suggest that searches for these impact ejecta layers will be more fruitful for determining how many times Earth was hit by big asteroids than searches for large craters.

Not exact matches

From the origin of the universe (big bang), to the origin of the moon (big collision), to the origin of lunar craters (meteor strikes), to the demise of the dinosaurs (asteroid impact), to the numerous sudden downfalls of civilizations documented by Jared Diamond in his 2005 book Collapse, catastrophism is alive and well in mainstream science.

The sooner we try to deflect an asteroid (perhaps by using the gravitational pull of a spacecraft to yank it onto a new course) the easier it will be, which is why Spaceguard is trying to catalog everything big enough to be a threat.

«We're inside of a big hole in the ground — a crater created by an asteroid 4 billion years ago — and for some reason there's a giant mountain in the middle,» Bell says.

A new census has dropped the estimated number of big asteroids that could inflict massive global punishment to at most 1000, all of which could be found by the end of the decade.

A new analysis by geophysicist Steven Ward and planetary scientist Erik Asphaug of the University of California, Santa Cruz, concludes that the biggest tsunami hazard arises from asteroids between 30 and a few hundred meters across, which may strike the ocean every 1000 to 100,000 years.

The mile - wide asteroid Braille, visited by the Deep Space 1 spacecraft in 1999, appears to be a big chip that broke off Vesta.

And he expanded the scope of big history by adding to it his concept of the contingency — the rare, unexpected event (like an asteroid collision) that changes the world in a blink.

Radioactive atoms would have melted the ice, making a sludgy mud that became rock, perhaps aided by gravitational pressure once the asteroid got big enough, or impacts with other objects.

This suggests that the biggest impact craters formed very early in Mars» history, and that later pummeling by asteroids mostly dented and dinged the surface.

Mercury and our moon hold other clues: big craters whose ages and patterns suggest a massive storm of comets and asteroids set off by the moving planets, in a pulse lasting 100 million years or so.

The radar results found that the bigger asteroids are covered with fine - grained dirt, the pulverized rock created by hundreds of millions of years of meteoroid impact.

According to the study, that would ensure that Earth would be re-seeded with life, following big, cataclysmic events like the Late Heavy Bombardment which happened approximately 4 billion years ago when the space environment around the Earth was dominated by untold numbers of big asteroids in the aftermath of its formation.

«While Ceres is a lot bigger than the candidate asteroids that NASA is working on sending humans to, many of these smaller bodies are produced by collisions with larger asteroids such as Ceres and Vesta.

The meteorite is an achondrite, a relatively rare type of space rock that comes from a planet or big asteroid — something large that generated enough internal heat early in its history to melt partially, producing a metallic core surrounded by rock.

Pixar's second release of the year imagines 1) Earth never hit by a big, bad asteroid, 2) dinosaurs that never went extinct as a result, and 3) a time when their human neighbors weren't yet paving and building on every available inch of the landscape.

These previous mass extinction events (also known as the «Big Five») are hypothesised to have been caused by combinations of key events such as unusual climate change, changes in atmospheric composition, and abnormally high stress on the ecosystem (except in the case of the Cretaceous, which was caused by an asteroid impact and subsequent effects).