Nasa how old is the earth

Scientists suggest that in about 7. How old is the Earth in human years? How old is the sun? According to NASA , the sun is about 4. How old is the Earth? Patterson measured the isotopic composition of lead from the Canyon Diablo meteorite and several other pieces of space rock, which were believed to date back to the disc of material from which Earth also formed.

Cite This! Try Our Sudoku Puzzles! More Awesome Stuff. Some star clusters have only a few hundred stars Pleiades while others have nearly a million globular clusters. Star clusters eventually get stripped to pieces by the gravitational tidal forces of the Milky Way and are in fact always losing stars from their outer peripheries.

There is no mystery to this. Its just basic gravitation at work. Some stars are so large, and radiate energy so rapidly, that they could not have contained enough hydrogen to radiate at such fast rates for long ages, because their initial mass would have had to be too immense. This is a rather typical example of how many discordant issues are thrown together into the same sentence to make the whole thing look like a major problem.

Stars come in a range of masses from over times the sun, to 0. The more massive stars have higher core gravities and so the central temperatures are much higher than for the sun. This means that nuclear fusion reactions there are occurring at a much more rapid pace.

The result is that massive stars use up their available core nuclear fuels in only a few million years or less, compared to the sun which can toodle along for 10 billion years. The comment about 'they could not have contained enough hydrogen Four types of stars radiate energy too rapidly to have existed longer than 50, to , years.

There are no such things as 'high-energy' stars. Astronomers speak of high-mass stars, and it is true that the more massive of these can live less than a few million years before going supernova. Researchers looking at rocks in southwestern Greenland also saw cone-like structures that could have surrounded microbial colonies some 3. In an effort to further refine the age of Earth, scientists began to look outward.

The material that formed the solar system was a cloud of dust and gas that surrounded the young sun. Gravitational interactions coalesced this material into the planets and moons at about the same time.

By studying other bodies in the solar system, scientists are able to find out more about the early history of the planet. The nearest body to Earth, the moon, doesn't experience the resurfacing processes that occur across Earth's landscape.

As such, rocks from early lunar history still sit on the surface of the moon. Samples returned from the Apollo and Luna missions revealed ages between 4. How the moon formed is a matter of debate; while the dominant theory suggests a Mars-size object crashed into Earth and the fragments eventually coalesced into the moon , other theories suggest that the moon formed before Earth.

Related : How was Earth formed? In addition to the large bodies of the solar system, scientists have studied smaller rocky visitors that have fallen to Earth.

Meteorites spring from a variety of sources. Some are cast off from other planets after violent collisions, while others are leftover chunks from the early solar system that never grew large enough to form a cohesive body.

Although no rocks have been deliberately returned from Mars , samples exist in the form of meteorites that fell to Earth long ago, allowing scientists to make approximations about the age of rocks on the Red Planet. With a radius of 3, miles 6, kilometers , Earth is the biggest of the terrestrial planets and the fifth largest planet overall. From an average distance of 93 million miles million kilometers , Earth is exactly one astronomical unit away from the Sun because one astronomical unit abbreviated as AU , is the distance from the Sun to Earth.

This unit provides an easy way to quickly compare planets' distances from the Sun. As Earth orbits the Sun, it completes one rotation every It takes That extra quarter of a day presents a challenge to our calendar system, which counts one year as days. To keep our yearly calendars consistent with our orbit around the Sun, every four years we add one day. That day is called a leap day, and the year it's added to is called a leap year.

Earth's axis of rotation is tilted This tilt causes our yearly cycle of seasons. During part of the year, the northern hemisphere is tilted toward the Sun, and the southern hemisphere is tilted away. With the Sun higher in the sky, solar heating is greater in the north producing summer there. Less direct solar heating produces winter in the south. Six months later, the situation is reversed.

When spring and fall begin, both hemispheres receive roughly equal amounts of heat from the Sun. Earth is the only planet that has a single moon. Our Moon is the brightest and most familiar object in the night sky. In many ways, the Moon is responsible for making Earth such a great home. It stabilizes our planet's wobble, which has made the climate less variable over thousands of years.

Earth sometimes temporarily hosts orbiting asteroids or large rocks. They are typically trapped by Earth's gravity for a few months or years before returning to an orbit around the Sun. Some moons are bits of rock that were captured by a planet's gravity, but our Moon is likely the result of a collision billions of years ago.

When Earth was a young planet, a large chunk of rock smashed into it, displacing a portion of Earth's interior. The resulting chunks clumped together and formed our Moon.

With a radius of 1, miles 1, kilometers , the Moon is the fifth largest moon in our solar system after Ganymede, Titan, Callisto, and Io.