Astronomy | Astrophysics Answers

Describe why numerical modelling of stellar structure requires both outward and inward integration calculation. Also,describe an iterative method to minimize the difference in the values of both outward and inward calculations.

For temperature around 1.5×10^7k in a stellar core,describe why it is hydrogen instead of heaviour ions which undergo fusion.Also,when the temperature is higher, describe why higher mass ions can undergo fusion.

In the outer core of a massive star the temperature is 10^8k.The mean particle weight is meo=0.62.calculate the density of this region if the radiation pressure is equal to thermal pressure.

Explain two assumptions behind Kelvin Helmholtz timescale

In a star's core the average mass number for ions which are not hydrogen or helium is 10.The mass fraction of hydrogen is 0.60,of helium is .38 and all other elements is. 02.Calculate the average ion mass in units of mh.

What is the phase of the Moon if it rises at 4:00 A.M.?

How does the theory of inflation explain the observed fact that our universe has a geometry that is close to being flat?

Select one answer?
1)Because curved regions of space-time have a larger effective density of false vacuum and hence will expand more rapidly.
2)Because the universe can only roll off the top of the mexican hat and hence stop inflation if its geometry is locally flat.
3)Because strongly curved regions will not last long enough for life to evolve
4)Because any smooth curved shape, if enlarged enough, will look flat locally.
5)Because if space was curved, regions of space with different laws of physics would collide, which is not observed.

A satellite orbits the earth in circular orbits. Find the period if:
a) The satellite is just above the surface of the earth.
b) The satellite is at an altitude of 300 km above the earth.
(Assume that air resistance can be neglected)
Provide your answers in minutes.

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