Thanks for this - it was very interesting and I thoroughly enjoyed it. I’ve never thought about this idea before. I also did some further reading and found that it ties into the Great Filter concept. I calculated roughly that human intelligence has existed for just 0.005% of Earth’s habitable...
Here is a screenshot taken from the website listed below:
https://www.icc.dur.ac.uk/~tt/Lectures/Galaxies/LocalGroup/Back/bigbang.html
If you go to the web page and watch the animation - do you think it is a reasonable analogy of the Big Bang and how it unfolded?
So since the Big Bang in the singularity sense marks the boundary of our current theories then it is only accurate to say our observable universe started with some very small finite size which was hot and dense? Is it better to use the start of inflation as the origin of the observable universe...
You said we don’t know the characteristics at t = 0 so you said no to the infinity of space but then you said it must have been infinite since the beginning? t = 0 is not the beginning then?
Hi,
I’m pretty new to cosmology and I’m trying to get my head around the Big Bang and the potential infinite extent of the universe as a whole.
There’s lots of misleading info out there but this forum and a few others have helped me and I just wanted to check I have the right idea.
The Big...
Thanks to all for your insights, it is much appreciated! @Hornbein - yes that's how I interpreted it and that makes sense to set the CC to a non-zero value to prevent the universe collapsing for an eternal static universe. This is what almost all the sources say. Some said that he didn't like an...
Hi, I've recently developed an interest for the history of the development of cosmology and find it very interesting. The key events I have been reading up on are:
1915 - Einstein's theory of General Relativity was published.
1923 - Hubble discovered a Cepheid variable in the Andromeda...
Thanks I think I can visualise it now. So it’s because they collide exactly edge on with no friction. I guess if ball B collided with some of its radius within ball A’s radius it would impart a force perpendicular to the centre line into A? Is that right? Thanks
Yeh I’m still struggling to visualise it. Ball B changes direction by moving through an angle of 90 degrees yet ball doesn’t changes it angle at all.
If the velocity is at an angle of 30 degrees will there not be a component normal to the line imparted on ball A?
Ah sorry I wasn’t clear. The only way to answer this question is if ball A recoils along the centre line. How do we know it doesn’t have any vertical component after the collision (vertical in terms of the plane of the surface).
Hi,
Here is the problem
What is required to answer this question is two assumptions. Firstly, the component of the momentum normal to the centre line is the same before and after. Therefore, secondly, A must recoil entirely in the horizontal plane. This is the only way to answer this question...
@davenn thank you for taking the time to write such a detailed response!
So it is bad to think of meteoroids having high speeds from the conversion of GPE to KE within Earth’s gravitational field? Their high speeds are from their orbital speeds around the Sun and the direction they strike the...
Ah yes of course it is in eV. Are the only EM radiations that interact with band gap theory just visible and UV then? IR by lattice vibrational excitations and high energy through scattering and ionisation?
I have been looking for an answer as to why lead attenuated gamma so well. It was...