have you ever looked up into the night
sky and wondered what it would be like
to be an astronaut
floating around in the space station our
group why are the astronauts floating
there's weightlessness in space you can
experience the kind of things why
they're weightless there is there a
gravitational force on them yeah but I
guess it's probably really weak not on
the astronauts because I just float
around it's like they'd float away if it
wasn't for the walls of the Space
Station right because they're outside of
Earth's gravitational well oh I see what
you've done here I see what you've done
here that's clever
hmm cuz cuz now I want to say that
they're outside of Earth's gravitational
pull but I just said that the moon
wasn't you doubt me well played
think about this the space station is
only about 400 kilometers away so if
you're in Sydney it's about well a
little further than the drive to
Canberra do you really think that the
earth exerts a big gravitational pull on
you but nothing on the astronauts a
short distance away forward well the
truth is this the force on the
astronauts is almost as much as the
force on you so why are they floating
while you're stuck here the answer is
the astronauts aren't floating they're
falling and not only that but the space
station that they're in is falling as
well
so why doesn't the space station come
crashing into the earth well the reason
is the space station and the astronauts
have a huge sideways velocity of nearly
28,000 kilometers per hour so even
though they are falling towards the
Earth
they're going so fast that as they fall
towards the Earth the Earth's surface
curves away from them and therefore they
never get any closer so the space
station and the astronauts inside are
constantly accelerating towards the
Earth's center but they never get any
closer and because both objects are
accelerating at the same rate the
astronauts feel weightless they have
this amazing sensation of floating