Unanswered Questions

8 questions with no upvoted or accepted answers
44
votes
0answers
1k views

How soon can the first stars form?

Introduction In our universe, the cosmic microwave background was formed approximately 400,000 years after the Big Bang. It was hot, but within a few million years after the Big Bang, it would no ...
17
votes
0answers
290 views

Plausibility of helium dominated atmospheres on super-Earths

I've been using this helpful diagram a lot for worldbuilding. Now I came to think about the fact that helium is more massive than hydrogen, thus a scenario where hydrogen escapes, but helium is ...
7
votes
0answers
175 views

Schwarzschild Metric in a universe with the same space time metric as that described in the orthogonal series, but with massive gravitons?

The universe described in the orthogonal series http://www.gregegan.net/ORTHOGONAL/00/PM.html is one, in which the minus sign in the space time interval is replaced with a plus sign. So this universe ...
3
votes
0answers
62 views

Appropriate Material for a Red Moon

I have some ideas regarding this, but thought I would check to see what you guys can come up with, as I found some of the ideas here often trump mine in originality and/or plausibility. So, I have a ...
1
vote
0answers
121 views

Can a system of 10 planets be stable if star is not on the main sequence?

My star is 2.17 Solar masses. For narrative purposes, I decided this so it will collapse in the theoretical Quark star. Could such a big star that isn't on the main sequence (Because its an A type, ...
0
votes
0answers
30 views

How to find the density of a planet and its core taking into account the gravitational compression in them?

Consider a planet $P$ of radius $r$ larger than Earth, whose mass is $r^3$. By the square–cube law, this planet will have the same density as the Earth... assuming that the gravitational compression ...
0
votes
0answers
35 views

What is the maximum equilibrium temperature that a mammal could evolve to tolerate?

Mammals live in some fairly extreme environments, but the most heat-tolerant ones all seem to cheat: e.g., they dig burrows to stay cool during the day and come out at night, avoiding the heat, or ...
-4
votes
0answers
181 views

Plants and Animals “Switch Places” - How Could This Have Happened?

Setting the Scene Say that you have a planet where, like on Earth, you have a taxonomic branch of its overall "Tree of Life" graph that has all the traits we associate with the "Plant" Kingdom on our ...