Wonder World Of Science: What's The Brightest Star In The Sky? (1987)

[Music] I wonder I wonder what do you wonder wondercat I wonder what's the brightest star in the sky what is the brightest star star in the sky if you're curious enough you can find out look over there are those Stars they seem to be getting brighter and brighter and brighter oh they're not stars at all they're airplane lights they look even brighter than the stars but that must be because I'm closer to them than I am to the [Music] stars but there's a bright star that looks like the brightest star in the sky it does but it doesn't twinkle like the stars do that's because it's not a star it's a planet it's the planet Venus part of our solar system you need a telescope to see that it's not really a star it's bright because the clouds all around it are lit up by the Light of the Sun but it's so far away that it looks like a star but it's not as far away as the stars are the brightest objects in the night sky aren't stars at all the moon for instance isn't a star it's lit up by the Light of the sun too that's why it's so bright it doesn't give off any light of its own when the astronauts were there the sun lit them just the same as it lit up the moon even the Earth is bright when the astronauts see it from space because it's lit up by the Light of the Sun the moon and the earth and the other planets are lit by the Sun but the sun is a star and the stars are bright because they're hot enough to give off their own light but I still wonder what's the brightest star in the sky you won't have to wonderand Long the brightest star in the sky is on its way it may not be the brightest star in the whole universe but it's the brightest star to us on Earth because it's our nearest star is it the sun is the sun a star that's right the sun is a star it's so bright it makes the whole Sky bright but where are the other stars now the sun makes the sky so bright you can't see the other stars when the sun is shining it's so bright you should never look directly at [Music] it if I put my sunglasses on I can look at it no even with sunglasses on you should never look directly at the sun scientists who work here know that this is a place where astronomers study the Sun a solar Observatory [Music] astronomers don't look at the sun directly when they study it they use mirrors that reflect the light of the Sun and let them look at its image instead of at the sun itself the Sun's light is reflected down a long Tuttle into the place where the astronomers work and even then they wear very dark glasses to protect their eyes even though the image they look at isn't nearly as bright as the sun itself the bright Sun lights our world and keeps it warm in the [Music] daytime even when it's cloudy or at night or when you can't see it it we still get its warmth because the sun is shining on the Earth all the [Music] time if the sun's always out there shining how does it get to be night well if we make these Shadows move a lot faster than they usually do maybe you'll be able to figure it out yourself hey clouds are making those shadows in the sunlight things are bright but in a cloud Shadow things are darker there's less [Music] light the cloud keeps some of the Sun's light from Shining through but the Cloud's moving and in the place where the shadow was things are brighter and warmer again now the sun is shining here [Music] again so now I know the Shadows are places where the Sun's light is blocked but I still don't know what they have to do with day and night you will just remember whenever you see a shadow you can always be sure that something is blocking some light I just noticed something else a thing that makes a shadow has a bright side and a dark side and the dark side of the tree is part of the [Music] Shadow remember anytime something blocks the light we get a shadow you said that [Music] yourself sunlight Shines on this part of the tree but the sunlight can't get through the tree to the ground where the sunlight doesn't come through we say it's a shadow but the front of the tree also blocks the light from the back of the tree the back of the tree is in the shadow of the tree too sure I see whenever a part of something is in the sunlight another part of it is in its own shadow like my head now one of my eyes is in the sunlight the other eye is in the shade but you're not looking at the sun good I can just turn my head and now both of my eyes are in the shadow my head makes in the shadow Out of The Shadow just by turning my head and do you know what else turns what the world it turns around and around in space as the Earth turns everything on the earth you for instance turns with it when the Earth turns and you go into its shadow then it's night where you are and then when you come out of the Shadow it's daytime where you are next now I see why knowing about Shadows helps me understand why we have day and night I thought you'd see so when the sun seems to be setting it's not really moving at all it's the Earth that's moving our part of the world is moving into the Earth's Shadow as it turns away from the Sun night is coming night time is the time for me to rest but now I know that the sun is the brightest star in the sky and I'll have a lot more to wonder about tomorrow when the Turning Earth moves me into the sunlight [Music] again [Music]