Why do scientists think that our sun is younger than the first stars that were formed?

Answer 1

The belief is that our sun is 4.5 billion years old, or thereabouts, while the Universe is 12 to 16 billion years old. There are also many observable stars which are older than our sun.

Answer 2

Astronomers think that the sun is a third-generation star. They base this on the amount of heavier elements, particularly iron, that can be seen in the sun's spectrum. These elements can only be formed in massive stars, which means that the sun must have formed from a nebula that contained the remnants of earlier stars. Stars with the sun's level of iron are called Population I. Older stars with very little iron are called Population II. There was a theoretical Population III of stars formed from the primordial hydrogen-helium cloud.

Other evidence of the Sun's relative youth comes from radionucleotide dating of meteorites, which puts the age of the solar system at a bit under 5 billion years. The sun's apparent stage of development according to stellar evolution theory is consistent with those estimates. Based on analysis of the microwave background and other evidence, the universe is 13.7 billion years old, and the first stars are believed to have formed within a few hundred million years of the Big Bang.

Answer 3

Because the evidence is part of our own bodies. the only place that elements heavier than Hydrogen and Helium can form is in a massive star that has long fused its Hydrogen and helium into increasingly heavier elements. These stars, when they die, explode in Super Nova explosions creating even heavier elements than Iron and spreading these neo atoms across the universe. eventually, these particles become caught in a gravitational well caused by dense clouds of cosmic dust that wouls still be mostly Hydrogen and Helium. Most of this cloud formed our sun, most of the rest formed the planets. Since the dust was here when our solar system formed, it stands to reason the star(s) that created the heavier elements within the newly forming solar system must have died long before our solar system formed. Hard as it may be to believe, the Calcium atoms in your teeth were once burning at unimaginably hot temperatures billions of years ago.

Answer 4

The earliest stars would only be composed of those elements that were formed from the Big Bang: hydrogen and Helium (with a bit of Lithium). The sun has elements farther along in the periodic table (like Carbon, Iron, etc) so it is not one of the first stars.

Answer 5

There are a few reasons.

First of all, we know from the CBR and other indications that the universe is about 13.8 billion years old.

The first stars, according to computer models, would have begun to ignite perhaps 100,000,000 years after the Big Bang, as hydrogen clouds began to condense into a dense enough form to make stars.

We know that the sun is not 13.7 billion years old for a few reasons:

1. Those initial stars were never as small as the sun. They were super-giant, up to 150 times bigger than our sun, because the available sun-making material was so much greater and other factors (like dark energy, matter, and black holes) were not yet a factor.

2. The sun's composition is all wrong for it to be one of those first stars. The only elements you'd expect to find in a first generation of star would be hydrogen and helium (that was all that existed.) Heavier elements like iron, gold, silver, carbon, etc. and other metals, materials, and gases only came into existence when they were literally blown out of primeval stellar cores by a supernova. The sun's composition is consistent with what you'd expect in a third generation star. By mass, hydrogen is 78.5% of the sun, helium 19.7%, oxygen 0.86%, carbon 0.4%, iron 0.14%, and everything else, 0.54%.

3. At the sun's current size and hydrogen depletion rate, it appears to have been operating in its main (yellow) stage for about 4.5 billion years. That's well short of the age of the universe. At the sun's current size, it consumes fuel too quickly to be as old as the universe. (The bigger a star is, the faster it consumes its fuel.)

Answer 6

One reason: they believe that the sun and our solar system formed from the scraps left behind when an ancient star blew apart. When that star blew apart, it left behind a nebula... gravity caused parts of the nebula to collapse and turn into the sun.

Second reason: Stars like the sun use hydrogen in a nuclear fusion reaction that produced helium. So, it loses hydrogen and gains helium as time passes. Based on the apparent amount of hydrogen and helium in the sun, it appears to be much younger than the age of the universe.

Answer 7

The chemical composition. The first stars pretty much had only hydrogen and helium in them Some of these first generation stars formed super nova and created heavy elements. Some of these heavy elements are in the sun so that means it was created from remnants of older stars.

Answer 8

Other stars are already dead. Black holes, stars that have gone supernova, all of them have reached the end of their life cycles. Stars run on fusion, so based on the size and density of a star, scientists know how hot it will burn and how long it will live. Our sun is about halfway through it's life. Other stars burned out long ago, so we know that they are older.

Answer 9

The sun contains elements that could only have been produced in a supernova - stuff that was made when an older star exploded.

Answer 10

Stars have a life cycle. Scientifically proven based on chemical composition and size. They can determine where in the life-cycle of stars our sun is. We observe others much older.