hello everyone and welcome back to our universe today we'll be answering the question why is space black on earth we have the Sun so close to our planet that it gives us an excellent level of light so therefore we can see everything around us in wonderful colors and at night we see the darkness because the light of the Sun is no longer there our Sun is like many of the other stars that we see at night each one of those stars is kind of like a Sun in its own location so basically if all the
stars are given off all this light why is the space so black to figure out why the sky is black we should probably explain why the earth has so much light and color the earth is surrounded by an atmosphere that contains gas water dust and dirt when the light of the Sun hits any of these objects it scatters or bounces off and this causes us to see the various colors it is our atmosphere that gives us the ability to see the light and the colors and this scattering effect lets us see the blue sky and
the gorgeous tones of the sunrise and the sunset space does have gas and cosmic dust but it doesn't have any atmosphere light will travel in a straight line until it hits something and then once this light hits something and it bounces off an object it is the atmosphere that allows the scattering effect and the ability to see all the colors in the spectrum the surrounding space around us appears black because there isn't a strong enough atmosphere to cause the scattering effect the light from the stars at the farthest end of the galaxy will take longer
to reach our eyes than those that are closer to the earth because light travels at a constant speed this means that when you are looking up into the universe and the surrounding stars in our galaxy you are looking at lights that may have taken tens of thousands of years to get to earth you are looking at light from the past and if you look even more in detail you'll see that the night sky is jam-packed full of galaxies and galaxy clusters that are millions if not billions of light years away so therefore you come to
wonder why the light of so many stars can't simply light up the universe the fact that there is some gas and cosmic dust particles should allow us to see some visible light one theory is stated that the universe is expanding away from Earth and therefore the light from the stars is also moving away when I say that the universe is expanding away from the earth I don't actually mean that the earth is the center of the universe because of all the space is expanding it's just from our perspective we see that everything else is expanding
away so as the universe keeps on expanding the wavelength of light gets longer and longer so therefore we end up having less and less visible light until there is no light that we can see the same can be said of sound you know when you hear in ambulance it sounds higher pitched and louder the closer that it is and the sound gets lower the farther it gets away from you this is known as the Doppler effect the final piece of this puzzle is to come to the realization that the universe isn't as old as we
originally thought it is believed to be just under 15 billion years old this age might not be old enough to allow light from all the stars to actually reach Earth so we can see it scientists have developed some technology that we can see light in other wavelengths that our eyes can't see are using this technology we see that space is still very black but we can see other colors that are usually hidden to our eyes and see things that are very faint for example it is given us a great chance to try and figure out
the gases that make up nebulas as each gas has a specific color and these wavelengths can be split up to observe great things within our universe for example gamma rays can look at compact objects in collision x-rays can look at neutron stars ultraviolet can look at quasars visible light look at stars infrared can look at galactic nuclei and radio can look at pulsars so even though our universe is not lit up like a Christmas tree we can still understand it and observe it in great wavelengths of light so I hope that's given you a good
understanding on why space is black and also give you a great insight into the wavelengths of light and as always if you've enjoyed the video click the like button and if you really really really enjoyed it click Subscribe thank you for watching you
