Why did the universe originally only contain hydrogen and helium?

The early universe (left) was too hot for electrons to remain bound to atoms. The first elements — hydrogen and helium — couldn’t form until the universe had cooled enough to allow their nuclei to capture electrons (right), about 380,000 years after the Big Bang.

What came first hydrogen or helium?

Scientists have inferred that helium hydride was this first, primordial molecule. Once cooling began, hydrogen atoms could interact with helium hydride, leading to the creation of molecular hydrogen — the molecule primarily responsible for the formation of the first stars.

Why is there so much hydrogen in the universe?

Hydrogen atoms are just protons. Protons are the only stable composite particles that can be formed from quarks. So once the early universe is cold enough for quarks to get into bound states, you end up with lots of protons, i.e., lots of hydrogen.

Why are hydrogen and helium The most common elements in the universe?

Hydrogen — with just one proton and one electron (it’s the only element without a neutron) — is the simplest element in the universe, which explains why it’s also the most abundant, Nyman said. Helium has two protons, two neutrons and two electrons.

Why helium is so abundant in the universe?

Helium is the second-most abundant element in the universe, after hydrogen, and accounts for about 25 percent of the atoms in the universe. Most of the helium in the universe was created in the Big Bang, but it also is the product of hydrogen fusion in stars.

When was most of the helium in the universe formed?

-Most of the helium in the universe formed during the ERA OF NUCLEOSYNTHESIS. -The GUT ERA refers to a time period in which the strong, weak, and electromagnetic forces were all unified. -The PLANCK ERA refers to a time period in which all four forces are thought to have been unified.

How was the universe created NASA?

Our universe began in a tremendous explosion known as the Big Bang about 13.7 billion years ago (left side of strip). A period of darkness ensued, until about a few hundred million years later, when the first objects flooded the universe with light.

Why was there no light at the beginning of the universe?

There were no stars, and there were no galaxies. After the Big Bang, the universe was like a hot soup of particles (i.e. protons, neutrons, and electrons). Light had formerly been stopped from traveling freely because it would frequently scatter off the free electrons.

How did the universe suddenly become transparent?

The Universe is uneven, and so are the stars and galaxies and clumps of matter that form within it. The Universe became transparent to the light left over from the Big Bang when it was roughly 380,000 years old, and remained transparent to long-wavelength light thereafter.

Why is there more hydrogen on earth than helium?

The 73\% hydrogen and 25\% helium abundances that exists throughout the universe today comes from that condensation period during the first three minutes. The 2\% of nuclei more massive than helium present in the universe today were created later in stars.