1-Light travels at exactly 299,792,458 metres per second in a vacuum (about 300,000 kilometres per second or just over 1 billion kilometres per hour).
2- light takes 0.0000033 seconds to travel 1 kilometre.
3- Light takes 8.32 minutes to reach us from the Sun.
4- Light takes 1.3 seconds to reach us from the Moon.
5- Light takes 26,000 years to reach us from the centre of our Milky Way galaxy.
6-The Moon is about 360,000 kilometres away from the Earth (and it is receding from us at a rate of about 4 centimetres a year as its orbit gradually speeds up).
7-The Sun is about 150 million kilometres away from the Earth (sometimes referred to as 1 astronomical unit, or 1 AU).
8-The centre of the Milky Way galaxy is about 26,000 light years, or roughly 246 quadrillion (246,000,000,000,000,000) kilometres
9-Hydrogen is by far the most common element in the Sun (and in the universe as a whole) and helium is the second most common.
10-Each cubic metre of air on Earth contains about 10 trillion trillion molecules
11-The electromagnetic spectrum is the range of possible electromagnetic radiation frequencies. They are usually described in terms of either their wavelengths (the distance between waves) or their frequency (the number of waves per second).
12-Black Body is an idealized object that absorbs all electromagnetic radiation that falls on it, without passing through and without reflection.
13-A scientist who studies physics is known as a physicist.
14-1921 Nobel Prize in Physics was won by Albert Einstein for his work in the field of theoretical physics.
15-Energy from food is usually measured in joules or calories
16-Uranus is the only planet in our solar system that rolls on its side like a barrel, while Venus is the only planet that spins in the opposite direction to Earth.
17-The fastest land animal in the world is the Cheetah, clocking a max speed of around 113 km per hour (70 mph).
18-The USA’s Mojave Desert is home to the world’s largest solar power plant
19-The Three Gorges Dam in China is the world’s largest hydroelectric power station.
20-During chemical reactions, chemical energy is often transformed into light or heat.