Science Questions

As a white dwarf evolves, the direction of its motion on the Herzsprung-Russell diagram is from upper left to lower right, which means that

Which meteorites are believed to be samples of primordial solar nebula material?

The particular feature of a comet that exhibits the most structure and always points away from the Sun is its

Most meteorites show evidence of having melted or of being fragments of asteroids that were once differentiated by heat. Carbonaceous chondrites, however, are believed to have never melted. Which one of the following sentences is NOT a reason we believe carbonaceous chondrites have never melted?

Meteoroid is the term used to describe a solid particle that

A piece of rock from outer space that reaches Earth's surface after surviving a fiery passage through Earth's atmosphere is known as a(n)

The astronomical event that is now thought to have occurred some 65 million years ago, resulting in the death of a large fraction of all living species and leaving a layer of clay containing an enhanced concentration of a rare metal, iridium, in the geological record in rocks throughout Earth was a(n)

In order of abundance, from most abundant to least abundant, the occurrence of meteorite impacts ("falls") is believed to be

What has been discovered in some meteorites that suggests that the formation of our Sun and solar system might have been triggered by a supernova explosion?

The nucleus of Comet Halley, as seen on close-up photographs taken by the Giotto spacecraft, is

A meteor shower, or the appearance of many more "shooting stars" at a particular time in the year from a specific sky direction, is related to which astronomical phenomenon?

The luminous trails of small dust particles that are completely vaporized in Earth's atmosphere are known as

In a single photograph of a comet and its tail, the only direction that one can determine with certainty is the direction

A chunk of rock and metal 10 km in diameter orbiting the Sun would be called a(n)

A small particle of rock orbiting the Sun would be called a

What mechanism controls the direction in which a comet's ion tail is aligned in space?

What physical process provides the energy for the ejection of a planetary nebula from a low-mass star?

In the process of helium shell fusion in a low-mass star near the end of its life, the star moves upward and to the right on the asymptotic giant branch of the Hertzsprung-Russell diagram. In this process, the star is

What happens to the surface of a low-mass star after the helium core and shell fusion stages are completed?

The nuclear process in which helium fusion occurs in the deep interiors of red giant stars produces