Helium is inactive. As known to us sun is made up of helium how does it glow ?

Question

Helium is inactive. As known to us sun is made up of helium how does it glow ?

Answer 1

The Sun is mostly hydrogen, with some helium mixed in.

The fusion that takes place at the centre of the sun fuses hydrogen into helium.  The helium that is produced is an "ash" (it does not fuse into any higher elements because the sun is not hot enough -- "only" 15 million degrees K).

The energy from the fusion eventually makes it way to the surface.  It makes the surface quite hot but nowhere near 15 million degrees.  The surface is a "measly" 5770 K (9900 F).

Any material that is heated to this temperature (even if it is chemically inert) will glow.  Just like the wires in a toaster (around 2000 K) or the tungsten filament in an ordinary lightbulb (3200 K).

Inside the bulb, the tungsten filament is surrounded by nitrogen.  Together, these are both inert.  However, it there is a leak, and oxygen goes in, the tungsten will immediately react (it will oxidize) and the lightbulb "burns off" (part of the wire will have turned to tungsten oxide and lay as dust in the bulb).

So, back to the sun, it does not matter that the surface is mostly hydrogen and helium.  It could have been tungsten for that matter.  At that scale, anything on the surface of the Sun can be considered chemically inert.  They just glow because of the temperature.

The heat jiggles the atoms so much that the loose energy is emitted in the form of photons (giving us light, heat and sunburns).

Answer 2

Helium is chemically inactive.

Helium can be active in nuclear fusion, but only at temperatures higher than that of our Sun's interior.

At present, the Sun's energy comes from nuclear fusion of Hydrogen (which is, in fact, the most common element in the Sun).  Once all the Hydrogen in the interior is gone, the Sun will go through a red giant phase, and then begin Helium  "burning", the fusing of Helium into heavier elements such as Boron and Carbon.

Answer 3

You mean helium is inert. That word refers only to its chemical properties, not its radiologic properties. Helium can be fused in stellar interiors to form heavier elements and release energy, but in our sun, it's mostly hydrogen fusion going on right now.

Answer 4

No, it's mostly hydrogen. And it generates energy by nuclear fusion, the same reactions as a hydrogen bomb.

Do people really not know this?

Answer 5

You're right, helium is chemically unreactive.  It only enters chemical reactions that involve a great deal of energy that change it ino a plasma ( a fourth state of matter).

However in the sun, the energy being released and the change taken place is due to fusion.  This is where atoms of one element are fused together to form new elements.  This releases massive amounts of energy and forms ne elements.

Answer 6

Current nuclear processes involve the fusion of HYDROGEN atoms to form Helium and a great deal of energy.  This makes the energy which powers the sun.  In about 5 billion years hydrogen reserves in the suns core will become depleted.  Then the force of gravitation will overcome the weakened heat and the sun will begin to shrink.  As it shrinks it will heat up.  At a certain temperature helium atoms will begin to fuse.  Chemical inactivity is immaterial in these conditions..  At this point the sun will begin to expand into its red giant stage.  Earth will become toast.