The universe in your hand

In the country one can see 4000-6000 stars, in the city only 300

The sun is 150 million kilometers from Earth.
When the sun is a watermelon,
the earth is 43m away and can only be seen with a magnifying glass.
There are 6500km to the earth
500.000km to the solar core

In the sun a nuclear fusion takes place.
E = mc² energy = mass x speed of light ²
In nuclear fusion, atoms combine -> the mass decreases, energy is released

The earth is a planet.
The sun is a star.

The sun will explode when it runs out of fuel, that will happen in 5 billion years on a thursday or up to 3 days sooner or later.

The Voyager 1 was launched in 1977. In 2013 she reached the outer border of our solar system. It has energy until 2025. It takes 18h for a signal at the speed of light to earth.

Proxima Centauri is the next solar system

One signal needs 1s from Earth to the Moon, another for the answer.
a sunbeam takes 8min 20sec from the sun to the earth.
From Proxima Centauri it is 4 years and 2 months for a signal.

The Milky Way is our galaxy with our and many other solar systems.
It contains 300 million stars.
If you spread 300m³ of sand, which is 300x 1mx1mx1m bigpacks full of sand and previously marked a grain of sand and then searches this one has found the earth.

Andromeda is our neighbor galaxy.
Andromeda and the Milky Way race at 100km / s.
They meet in about 4 billion years.
A light-speed contact with Andromeda takes 2.5 million years.
So far 54 galaxies are known.
These are up to 8.4 million light years away from us.
After 13.4 billion light years, we reach the field of last scattering.
According to current knowledge, the world could have come into existence here. Behind it, however, other multiverses can hide as well.

Cosmological principles
The laws of nature are the first cosmological principle
There is nowhere in the universe a privileged position, 2nd cosmological principle
Galaxies continue to move away from each other, the universe expands, the third cosmological principle.