Expansion History and Dark Energy

Question 1

How does Hubble’s constant change with time

Answer 1

Cosmic Expansion, Evolution of the Universe

Question 2

Open Universe

Answer 2

open universe refers to a cosmological model in which the density of matter in the universe is less than the critical density. In an open universe, the spatial geometry is negatively curved, similar to the surface of a saddle.

Question 3

Closed Universe:

Answer 3

A closed universe is a cosmological model where the density of matter in the universe is greater than the critical density. In a closed universe, the spatial geometry is positively curved, resembling the surface of a sphere

Question 4

Critical Density:

Answer 4

he critical density is a concept that represents the exact amount of matter (including both ordinary matter and dark matter) and energy required for the universe to be precisely flat. It is denoted as Ω = 1,

Question 5

Dark energy; mix of contents

Answer 5

Dark energy is a hypothetical form of energy that is proposed to explain the observed accelerated expansion of the universe. (Λ). t consists of approximately 68% dark energy, 27% dark matter, and 5% visible matter. These component

Question 6

Sandage-Loeb test

Answer 6

to measure the expansion rate of the universe at late cosmic times

Question 7

he Andromeda–Milky Way collision

Answer 7

The Andromeda–Milky Way collision refers to a future cosmic event in which the Andromeda Galaxy (also known as M31) and the Milky Way Galaxy, the two largest galaxies in the Local Group, are expected to collide and eventually merge together. 4.5 billion years from now