From how it began to its ultimate fate

[>] The diameter of earth is 12,756 km
[>] The outermost planet, Neptune, orbits sun at a distance of 4.5 billion km
[>] The brightest star in they sky is "Sirius" - 8.6 light years away.
[>] 200 billion estimated number of galaxies in the observable universe
[>] The average rate at which the objects move away from each other in the universe due to expansion of space is 21.5 km per second per million light years
[>] The distance of an object at the limit of our observable universe is 46.5 billion light years.

The mos accurate way of measuring distances to remote galaxies is to look for standard candles - rare objects that are bright enough to across vast distances
They obey the physical rules that reveal their intrinsic luminosity or light output
The most useful standard candles are variable stars called Cepheids, whose pulsation period is linked to their average luminosity.
Hubble's law links the distance of a remote galaxy to the speed at which it is moving away from us.
Hubble's law applies because the universe as a whole is expanding carrying distant galaxies away from each other like raisins in a rising cake.
The wider the separation between galaxies, the faster they move apart.

The rate of expansion - Hubble's constant - around 21.5 km per second per million light years of separation.
Average, galaxies 10 million light years apart are receding from each other at around 215 km per second.
The beginning of the universe about 13.8 billion years ago.
Origin of the big bang theory - our best explanation for how the universe began.

Light moves at 299,792 km per second
The further away we look in space, the further we are looking back in time, since light must have left the objects long ago to reach our telescopes now.
The first objects to be spotted at immense distances were quasars - galaxies with monster black holes at their centres that have not yet settled down into a quiet slumber, still actively feeling on gas and dust from their surroundings.
Hubble space telescope and James Webb space telescope (launched in 2021) have allowed astronomers to detect light from fainter galaxies even closer to the big bang.

Since radiation has only had 13.8 billion years to reach earth, it is impossible for any information to reach us from remote parts of the universe beyond 13.8 billion light years.
Beyond these lies the cosmic dark age, a period of around 400 million years after the incandescent big bang had cooled into invisibility during which matter coalesced in darkness.

Matter is controlled by four fundamental forces, which influence different types of matter in different ways.
Visible matter is composed of tiny atoms that are bound by each other by the electromagnetic forces. These are built from even smaller elementary particles held together by both electromagnetism and two nuclear forces that are much powerful but only operate across tiny distances.
When matter accumulates in large quantities, gravitation or gravity comes into play. It attracts objects with mass. It's extremely weak between individual atoms, but grows stronger as they accumulate in bulk.

The visible matter that produces and interacts with light and other forms of radiation amount to just 5% of all matter in the universe.
Dark Matter is not only dark, but also transparent and completely unaffected by the radiation.
The current best guess is that dark matter is predominantly made from one or more unknown types of elementary particles, known as weakly interacting massive particles (WIMPs)
The presence of so called dark energy was discovered in the late 1990s when astronomers found evidence that cosmic expansion is currently accelerating rather than slowing down as we might expect due to gravity of all matter in the universe.
It must account for around 71% of all energy in the universe.

The universe is 13.8 billion years old, but still it is young, with some stars shining today, our sun is more than one third age of the universe.

This argues that just as our universe arose from one tiny region within the original bog bang and was then blown up by a sudden event called inflation, the raw material of the big bang is still out there, giving rise to new universes with the potential for very different physical parameters to ours.

This is rooted in quantum mechanics, that governs particles on a sub atomic scale, within which events always carry a degree of uncertainty. According to many worlds interpretation, every possible outcome of a quantum event occurs, but each one happens in its own distinct universe. In this sense, a truly infinite number within which things happen to have played out a certain way. Pic:

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