Critical Density: H0=70km/s.MPC, Fate of Universe

Thread starter b_o3
Start date Mar 13, 2007
Tags

Critical density Density

AI Thread Summary

To find the critical density (p0) for the universe with H0=70 km/s/Mpc, the relevant equation is p0 = (3H0^2)/(8πG), where G is the gravitational constant. The calculated critical density is approximately 9.2 x 10^-30 gm/cm^3. Given that the average density of the universe is 5 x 10^-28 gm/cm^3, which is greater than the critical density, the universe is likely to be closed and will eventually recollapse. This indicates that the fate of the universe is to stop expanding and reverse into a Big Crunch scenario. Understanding these calculations is essential for grasping the universe's ultimate fate.

Mar 13, 2007

b_o3

hello, can anyone help me with this problem please:

For H0=70 km/ S . MPC , what is the critical density (p0) for the universe in gm/cm^3? . if the average density of the universe is 5 * 10 ^ -28 gm/cm^3 , what is the fate of the universe.

thanks ,

Physics news on Phys.org

Mar 13, 2007

Dick

Science Advisor

Homework Helper

You don't know ANY relevant equations? You need to make a start at a solution and prove you are stuck before anyone can help.

Thread 'Rolling without slipping on a curved surface'

Kindly see the attached pdf. My attempt to solve it, is in it. I'm wondering if my solution is right. My idea is this: At any point of time, the ball may be assumed to be at an incline which is at an angle of θ(kindly see both the pics in the pdf file). The value of θ will continuously change and so will the value of friction. I'm not able to figure out, why my solution is wrong, if it is wrong .

View full post »

Thread 'Voltmeter readings for this circuit with switches'

TL;DR Summary: I would like to know the voltmeter readings on the two resistors separately in the picture in the following cases , When one of the keys is closed When both of them are opened (Knowing that the battery has negligible internal resistance) My thoughts for the first case , one of them must be 12 volt while the other is 0 The second case we'll I think both voltmeter readings should be 12 volt since they are both parallel to the battery and they involve the key within what the...

View full post »

Thread 'Trying to understand the logic behind adding vectors with an angle between them'

My initial calculation was to subtract V1 from V2 to show that from the perspective of the second aircraft the first one is -300km/h. So i checked with ChatGPT and it said I cant just subtract them because I have an angle between them. So I dont understand the reasoning of it. Like why should a velocity be dependent on an angle? I was thinking about how it would look like if the planes where parallel to each other, and then how it look like if one is turning away and I dont see it. Since...

View full post »