What if the Earth's star was two stars? Like, the kind that orbits each other. If there were that in the middle of the solar system, what would conditions on Earth be like? Would life as we know it be able to exist?
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I'm unclear what you mean?I am getting more unhappy, as in other threads in the last two minutes.
Now spacetime is pulling together because of gravity?
I was being facetious with the speculative nature of space expansion. I have only subjective opinions. There are no objective arguments for how space expands so far, I expect. DE is just a label, not an explanation.Like Gravity thread. You said spacetime thickens (?).
The only galaxies approaching us are ones nearby. There are no known distant galaxies that do not fit the Hubble-Lemaitre constant, AFAIK. If any galaxy did not fit appropriately in this model, it would be big news. It's likely that only a number of our Local Group of galaxies have the only blueshifts (e.g. Andromeda).Helio, I am beginning to have more doubts about expansion. I am happy in principle about BB, but some issues are emerging about closer to origin (galaxies approaching, and now (separately) about double stars). This concept of jiggling around with spacetime worries me.
I would think that it does apply to the Local Group, but the result is not that noticeable.It just has to be recognised that HL applies above certain parameters but not below.
Yes, this is how I see things move in relation to both expansion and gravity. The two can be treated as separate vector forces.Andromeda is receding due to space expansion at a rate of 54 km/sec
Andromeda net movement is towards us at 112 km/sec due to gravitational attraction.
Both the expansion of space and the attraction of gravity have a significant effect on the rate at which the two galaxies move relative to each other.
The first graph is the measured radial velocity (see data link). The second simply subtracts the Hubble flow (H-L constant) of 70kps per 3.26M lightyears of distance. [Hmmm, did they change "Hubble Flow "to "Hubble-Lemaitre Flow"?)I don't understand HL Velocity and Adjusted Velocity. Which is the actual recessional (or opposite) velocity. I want a direct comparison with the usual recessional velovity / distance graph.
The negative values for RV are for velocities towards Earth, positive are the recessional velocities.Ahh! I want to plot exactly the same as the usual graph. Is that (recessive) velocity in the table.
There are both neg. and pos. values for vel. So I'm not clear what you are saying.The other (non adjusted?) velocities are all positive.