Scientist say that the distance between the Earth and the Sun is 1 astronomical unit.
1AU = 150,000,000km
The distance to the edge of the solar system is 30.07AU
Proxima Centuri is the closet star to our solar systems. It is 39,900,000,000km. In astronomical unit it is 271,000 and its is 4.2 light years away.
A light year is the distance it takes for light to travel in 1 earth year. Light travels 300,000km every second. It takes 8 minutes for light to reach us from the sun, so it takes 4.2 light years for the light for our closet star Proxima Centuri to reach us.
The Milky way is a spiral galaxy, it is 10,000 light years away to travel from one side to the other. Our galaxy is one of billions in the Universe, they estimate that it's about 93 billion light years across.
Methods of collecting data about the Universe
Naked Eye: Humans use visible light that we can see to gather data.
Telescopes: Use the EM spectrum to gather information.
Telescopes help you see object in the universe clearer and in more detail than the naked eye and they also give you an accurate source as it real. But there are problems.
Telescopes on Earth find it hard to detect light because of the Earths atmosphere. The Earth atmosphere absorbed most of the light fro space before reaching the Earths ground. If you want to observe the frequency absorbed then you have to go above the atmosphere to achieve that.
Light pollution (light thrown up into he sky from street lamp) makes it hard for the telescope to pick out dim objects. Air pollution (dust particles) reflect and absorb the light that is coming from space so for a telescope to capture light, telescopes should be placed on top of a mountain because there is less atmosphere or far away from city.
However, there an easier way to observe the light from space by using a space telescope. The first one of it kind was called Hubble which was launched by NASA in 1990. The Hubble space telescope is able to see objects fainter then you can see unaided from Earth.
Different Telescopes that detect different types of the EM wave
Optical telescopes detect visible light. They are used to look at objects close by and in other galaxies, but not all objects in space are detected by visible light.
From 1940 onwards, telescopes were developed for all parts of the EM spectrum.
X-ray telescopes can see high temperature vents in space e.g exploding stars.
Radio telescopes were responsible on helping discover cosmic background radiation which helped scientist to learn about the origins of the Universe.
Telescopes are improving, big telescopes give better resolution. Improved magnification helps us look further into space so more and more galaxies are being discovered.
Discovering more galaxies tells scientist about their life cycle. Picture from the Hubble telescope show different stages of their forms which tells them…