how gaseous elements can have absorption and emissions lines and why they are useful for astronomers?​

u=13

v=30

s/t=u+1\2at

=13+431/2

=13+265.5

=278.5

the only real purpose of sputnik 1 was to beat the us into space. we were getting close to launching a useful satellite, explorer 1 - which launched on january 31, 1958. the ussr had to beat that, so they launched sputnik 1 on october 4, 19