Is it a star ?

yep that's venus you're looking at. it is the third brightest object in the sky, after the sun and the moon, and it can in fact cast shadows. venus is known as the "evening star" or the "morning star" as it only appears after sunset or before sunrise at certain times of the year.

there is a strong theory that Venus is the 'star' which the magi followed to jesus' birthplace! venus will be visible in the night sky for another 2-3 months and will be brightening all the time as it is getting closer to earth at present.

when you look at venus in a scope, when it is close to earth it looks like a crescent moon! venus and mercury are the only planets to show this 'phase' effect when viewed from earth - this is because they are the only two planets which are closer to the sun than us.

the reason venus 'shines' is because it is 'lit-up' (or reflecting) by light from the sun. venus is permanently shrouded by sulphurous clouds, these particular type of clouds are very reflective, reflecting around 65% of sunlight which hits them.

similarly, the only reason we can see the moon, mars, mercury, asteroids, comets and other solar system objects (satellites orbitting earth) is because they are reflecting sunlight.

if you were standing on the surface of mars (or whichever planet), you would indeed see earth as a pale blue dot (a term coined by Carl Sagan). standing on the surface of the moon, the earth would look pretty spectacular - would appear around 4 times the size of what the moon appears to us here on earth.

jAH