A redshift reveals how an object in space (star/planet/galaxy) is moving compared to us. It lets astronomers measure a distance for the most distant (and therefore oldest) objects in our universe
Define and measure the speed
choose this
heliocentric theory = Ptolomeu
radioactivity = Becquerel
reflecting telescope - Newton (not sure)
Look at the photo attached
Hope this helps ʕ•ᴥ•ʔ
Alfred Wegener believed that all of the continents were originally attached! By looking at the map, you can see that Africa and South America look like they were once joined. This 'super continent' was known as Pangaea. He also found fossils that proved his point.
Hope this helps :)