Questions tagged [helium]
Second lightest element in the periodic table
22
questions
-4
votes
1
answer
81
views
Did liquid helium help the solar system to form by cooling the nebula that collapsed to form it?
Was the gas cloud that collapsed to form the solar system cooled by liquid helium at some point in time? I ask because the Cosmic microwave background had a temperature around 3K when the solar system ...
user50918
7
votes
1
answer
384
views
Are red giants still primarily made of hydrogen? What is their exact composition?
How much lower is the ratio of hydrogen to helium in a red giant vs a 'normal' main sequence star like our Sun?
Also, how low does the ratio get at the end of a red giant's life? (Just before it ...
- 5,307
9
votes
3
answers
310
views
What is the elemental composition of the Sun overall, rather than at the photosphere?
Many sources claim that the Sun is around $70-74\%$ hydrogen and $25-27\%$ helium by mass, or $91\%$ and $9\%$ by atom count, without any further caveats - e.g. 1, 2, 3. I believe these sources are ...
- 142
6
votes
1
answer
134
views
How do we estimate the amount and distribution of Helium in interstellar and intergalactic space?
Quoting from wikipedia: Helium
... is the second lightest and second most abundant element in the observable universe (hydrogen is the lightest and most abundant). It is present at about 24% of the ...
- 1,444
0
votes
0
answers
75
views
What is the percentage of ortho to para helium in the Universe?
Helium is the second most abundant element in the Universe with 24%.
But I could not find any data about what percentage is para to ortho.
In my opinion there will be slightly more para helium because ...
- 149
4
votes
1
answer
222
views
What is the percentage of ortho- vs. parahelium in the sun?
Parahelium (P) has its 2 electrons with opposite spins and S=0. Orthohelium (O) has parallel spins and S=1. The energy levels of P are a little bit higher than O. Maybe this leads to easier building ...
- 149
23
votes
2
answers
10k
views
Is Jupiter a failed star?
The elemental make-up of Jupiter is about entirely hydrogen and helium, along with a very small fraction of the atmosphere being made up of compounds such as ammonia, sulfur, methane, and water vapor. ...
- 359
7
votes
1
answer
743
views
What is the most appropriate way to estimate the helium composition of a star?
Say we have to estimate the helium content in Proxima Centauri.
We begin by calculating the content of helium in the Sun (source): $24.85$% of $2.10^{30}$ kg.
Mostly all the energy is generated due ...
- 181
5
votes
2
answers
2k
views
Where can I find Helium 3 in our solar system?
What are the best locations within the solar system to find Helium 3 excluding the Sun? Where is Helium 3 most abundant after the Sun?
- 153
5
votes
1
answer
383
views
How much helium has been created since the Big Bang?
When I try to find figures for the amount of helium today and just after the Big Bang, I get similar figures. I was expecting that all of the stars since then would have created more helium. Is the ...
- 369
9
votes
1
answer
356
views
What percentage of Helium-3 is primordial vs produced in stars
I tried to research but what I found is pretty limited. A very tiny but non zero percentage of primordial matter was Helium-3 or 3He.
Stars produce 3He as part of the proton-proton chain but they ...
- 24.1k
3
votes
1
answer
260
views
Helium rain inside metallic hydrogen within Jupiter, conditions and experiments?
In response to today being pi day (also see http://www.piday.org/), NASA has published it's fifth annual pi in the sky day 5 activity set (see also NASA goes the distance and Celebrate Pi Day with ...
- 30.7k
6
votes
3
answers
645
views
Can I slice off a piece of the Sun?
Bear with me. I want to explain this to my 6 and half year old.
If, all things being equal, we could reach out to the Sun with a suitable implement, a gigantic space knife, could we cut a piece off ...
- 179
6
votes
1
answer
213
views
Why Helium could be produced in first minutes of big bang but not heavier elements
At what extent could be sure that no heavier elements than helium could be produced, if we know that matter in universe today is about 25% composed on helium, why could be so sure that the kind of ...
- 101
3
votes
1
answer
211
views
Ionization Fraction of Helium in alternate, He dominated early universe
I'm asked to verify an expression for the ionization fraction of helium in a universe in which helium dominates baryonic matter.
I'm given that the ionization fraction $X = \frac{n_{He^+}}{n_{He^+}+...
- 205