Ultimate cosmology quiz

[BrainForce]

Ok! u got it precisely that nebula question u have answered correctly,with second question i.e.

classify it further

I just wanted u to do some more brainwork.But what u answered was sufficient.

How much time a body will take to orbit the earth,if earth somehow changes into a black hole?

Please consider the body as not effected by that "black holed earth" gravity nor by any other physical effects ,consider it hypothetical body moving on that black surface.

[Jay-qu]

And is that black hole precisely the mass of earth, and is the body at the same distance from the black hole as it was from the centre of the earth?

[BrainForce]

Oh!I forgot to give u speed:doh:

The body is moving with the speed equal to that with which asafa powell ran while making the world record.

 

The body will be moving on the surface of earth when the earth becomes a black hole.Thus distance to be covered changes with changing of radius.

 

The mass is also the same,teh change is in radius

[Jay-qu]

So it always stays at the surface of the collapsing Earth?

[BrainForce]

Better if u say " collapsed " earth.

 

The body starts moving when the earth has completely changed into black hole

Don't take the body as moving while the earth is collapsing,it will be much more complicated then.

[Jay-qu]

Ok, but that still doesnt answer the question of how far from the black hole the object is orbiting..

[BrainForce]

on its surface only.

[cwes99_03]

OK so here is my rendition of the question.

 

How fast is a body moving if it is at r distance from a black hole of mass m, where r is the radius of the earth and m is the mass of the earth?

[BrainForce]

May I eleborate each and every aspect of question broadly to uproot any misunderstanding developing in your minds.

 

A body with a mass equal to that of earth have changed into a black hole.

Now an object which experiences no ill-effects of black hole, has to start its journey from a point on black hole's equator and has to come back at the starting point once again.The object is moving with the speed with which Asafa Powell ran while he made the world record.

 

I want the time (in seconds) which the body takes to do so ?

[Jay-qu]

well there is still some information missing..

 

by black holes equator do you mean event horizon? and you say it has to get back to its starting point, but you havent specified from where it started..

[cwes99_03]

Ok, so I left out the v equals speed with which Asa Powell ran world record run.

 

This sounds stupid to me, I'd just post a new question and move on.

 

Maybe he wants you to compute the time dilation experience or something to that effect. This is just a poor question.

The equator he is refering to is the distance from the center of the earth to the surface at sea level at the equator.

 

How long does it take for an object moving at velocity v at distance R from point mass M to circle point mass M and return to starting point? Would have been interesting if we had to calculate the geocentric velocity or whatever but instead it is simply, 2*pi*R/v and calculate in the time dilation effect cause by being in close proximity to M (which as far as I can tell is so negligible not to matter because M is too small and the circumference is too short).

 

Next question please, this is a quiz not a calculational test.

[BrainForce]

Cold dark matter theory developer's middle name starts from a letter, the same letter is in the starting of a limit which describes orbital system of planets or sattelites. What letter am i talking about ?

[Jay-qu]

R?

[cwes99_03]

Don't just answer the question, give your reason for chosing the letter. Answer the question with logic :cocktail:.

[Jay-qu]

R for Roche limit :)

[BrainForce]

:D o u got it right !R is for roche limit and joel .R Primack is the name u are familiar with whenever u are studying or doing research on cold dark matter.

[Jay-qu]

yay for me! And i didnt fully guess that one.. I only knew the Roche limit, not the guys name :D

 

What is the point of the SETI protocol?