How do scientists think a star is formed?

Answer 1

The Earth and all the planets are formed 4.5 billion years ago with interstellar hydrogen gas and heavier elements previously formed in earlier stars that had exploded.

The Sun, a young star, consists almost entirely of hydrogen and helium, which are being converted into other elements by a process of fusion, which generates the energy radiated by the Sun. However, the Sun produces insignificant amounts of elements heavier than carbon, since this fusion requires much higher temperatures. Some stars do create heavier elements, and as they reach the end of their lifespans, they explode as supernovas, releasing these elements (and creating still more, notably the radioactive ones).

Sometime more than five billion years ago, supernovae had exploded in our neighborhood of the Milky Way galaxy, creating and spewing out vast volumes of heavy elements. A tiny percentage of this material (but still a huge amount by earthly standards) was captured in the disk of gas that would form our Sun. Scientists are beginning to discover planets around other nearby stars, indicating that terrestrial planets (formed of heavy elements) also exist around other stars.

Around 4.5 billion years ago, this gas coalesced into a small number of balls, one of which was the Earth. These balls, or planets, were very hot but cooled, forming an outer crust on the smaller ones. The Earth could have continued to cool until it solidified. However, with radioactive uranium as one of the heaviest elements, the Earth's core can maintain an extremely high core temperature almost indefinitely. The discovery of near-surface geothermal "hot rocks" provides an example of the same process.

The Earth's surface has not always had the same form or with the same continents as it has now. A process of plate tectonics has the continents drifting (at an incredibly slow but measurable pace) across the surface. They split apart and ram back together to form new land masses. The Himalayan mountains were formed when the Indian land mass pushed into the southern boundary of the ancient Asian land mass, folding the crust and forming mountains. Other mountains were formed by similar processes.

The Earth's crust was originally formed from igneous rocks, much like the rocks formed when lava cools. These rocks gradually weathered away into sand and silt, which were deposited in the valleys and on the ocean bed. Here, they were compressed into sedimentary rocks such as sandstone and shale. The earth's surface is constantly changing, and many sedimentary rocks were later uplifted to form new mountains.

AnswerIt was made by something special, God. The King James Bible says in Genesis 1:1 that "In the beginning God created the Heavens and the Earth."

Answer 2

Earth's original atmosphere was probably just hydrogen and helium, because these were the main gases in the dusty, gassy disk around the Sun from which the planets formed. The Earth and its atmosphere were very hot. Molecules of hydrogen and helium move really fast, especially when warm. Actually, they moved so fast they eventually all escaped Earth's gravity and drifted off into space.

Earth's "second atmosphere" came from Earth itself. There were lots of volcanoes, many more than today, because Earth's crust was still forming. The volcanoes released

1. steam (H2O, with two hydrogen atoms and one oxygen atom),
2. carbon dioxide (CO2, with one carbon atoms and two oxygen atoms),
3. ammonia (NH3, with one nitrogen atom and three hydrogen atoms).

Much of the CO2 dissolved into the oceans. Eventually, a simple form of bacteria developed that could live on energy from the Sun and carbon dioxide in the water, producing oxygen as a waste product. Thus, oxygen began to build up in the atmosphere, while the carbon dioxide levels continued to drop. Meanwhile, the ammonia molecules in the atmosphere were broken apart by sunlight, leaving nitrogen and hydrogen. The hydrogen, being the lightest element, rose to the top of the atmosphere and much of it eventually drifted off into space.

Answer 3

This is a really tough question . I guess almost everyone on this earth would want to know the answer . Even scientists have been trying to find the answer since thousands of years . No wonder how many more years we will have to wait to get the right answer to our question related to this topic .

Answer 4

Asteroids smashed by the force of gravity and fused together from the heat of the collision. As more and more asteroid hit into each other the asteroid got bigger and bigger. Eventually, the asteroid's gravity became strong enough to form into a spherical shape (well it wasn't perfectly spherical). After millions of years the surface cooled. Our early planet was formed.

Answer 5

gas and other particles were pulled together by gravity and it formed the Earth (gravity pulls objects into spherical form that is why all planets, stars, etc. are round). lava oozed out of early volcanoes and formed rock, asteroids struck the earth, then (this is a theory) water formed by a series of icy comets, the earth cooled, life began in the seas, etc.

Answer 6

There are a number of conflicting theories, but the current most likely explanation (and you should know that different explanations become the "most likely" every time we learn something new and unexpected about the Moon) is that the Moon formed from the debris left over when a small planet - perhaps the size of Mars! - crashed into the proto-Earth and merged with it.

This provides some possible reasons for a couple of interesting facts. For example, the Earth is the densest planet, and we believe that the iron core of the Earth is larger than the cores of the other planets. So the iron core of this other planet probably merged with the core of the proto-Earth.

The impact would have shattered both planets, and the Earth, we think, formed out of the wreckage. Debris blasted into space might have come together to form the Moon.

However, there are some problems with this theory; none of the mathematical models of how such a collision might have occurred actually produce anything like the Moon. So there are some things - probably amazing things! - that we don't know about how the Moon formed.

Answer 7

The Earth formed about 4.5 billion years ago, not long after the Sun.

After the Sun formed, a disk of leftover debris orbited it. This debris of gas and dust would, through the force of gravity, coalesce to form the planets and all other solar system bodies.

Gravity pulled the dust and gas into chunks. These chunks further clumped together and grew larger and larger, until they began to form a spherical planet. This is how all the planets formed, including Earth.

Answer 8

In a word..Gravity. First off dust particles accumulate which increases their mass and therefore increases the gravitational pull. This attracts larger bits and so on and so forth until either the object runs out of material to attract or is assimilated into another, yet larger object with a greater gravitational field

Answer 9

Just at some place in space, about our current distance from the center of the galaxy, in a vast interstellar cloud where other stars also formed. The dust cloud gradually formed into a solid mass of a planet about 4.5 billion years ago.

Answer 10

We just started learning this at school....there is alot of steps to it. The protostar starts in the nebula.

Here is a few:

Do you mean like how does a low/medium mass protostar form to a low/medium mass star?

They go through nuclear fusion. It has to be 20 million degrees for that to happen,

Low/medium mass star to a red giant?

When a low mass star dies they become a red giant

This one is hard to explain but here i go. Red giant to a planetary nebula?

When a red giant stops glowing, the shell drifts away it forms the planetary nebula.

Planetary Nebula to a white dwarf?

Gas and dust leave the core.

White dwarf to a black dwarf?

When a white dwarf stops glowing.

Now i will explain when a Nebula forms a High Mass proto star:

High mass protostar to a high mass star?

Nuclear fusion....20 million degrees.

High mass star to a supergiant?

When a high mass star dies.

Super giant to a super Nova?

When a super giant explodes. There is more to it but i cant remember...sorry

Now a super giant can form a black hole or a neutron star...depending on the mass of the star. The higher the mass it would form to a black hole. So then a low mass star would form to a neutron star....

I hope that helped!