# How fast does Venus move as seen from the earth?

So last night I was about to sleep with the window in front of me. there was a 3 inch gap between the curtains that let me see a small portion of the sky. I could see something magnificently bright in the sky that couldn't be anything but Venus. So while I was looking at it for about 1-2 minutes it gradually moved out of my sight. That seemed pretty fast. I mean I kinda estimated that with such a speed it could move from east to west in less than 2 hours. So is that normal?

• Ganbustin.Good answer no more to be said really with my grand children we talk of 1degree = 4minutes and demonstrated transit of the moon(1/2 deg) took 2minutes – Colin Shorey Jan 14 '15 at 9:58
• I just found this thread - I saw the EXACT same thing one week ago. Venus was shining so bright that my boyfriend told me to come to the window to look at it. We got our binoculars out and used an app to determine that it was Venus. About 20 minutes later my boyfriend went to another room in the apartment and I was sitting on the couch, still looking out the window at Venus, when suddenly it started moving. Rapidly. First I thought my eyes were playing tricks on me but it kept moving until it was out of my line of vision completely. I called my boyfriend and said "come here, it moved. it's gon – Lex Jan 4 '17 at 22:30
• e!" He didn't believe me until he came and looked and saw it was nowhere to be found. So bizarre. – Lex Jan 4 '17 at 22:30
• Well, once I got tricked by an airplane thinking it was a moving star. lol! But if your app says it's Venus, it probably is, or maybe you were witnessing International Space Station? Are you sure it was not a cloudy night? And perhaps the shiny object was camouflaged by a big cloud? Happens to me a lot. – ye9ane Jan 6 '17 at 7:46

The Earth rotates on its axis once every 24 hours. (Well, actually a little less, by about 17 minutes, but close enough.) That's $360^\circ$ in 24 hours, or about $15^\circ$ per hour. $15^\circ$ is 30 times the width of the Sun or Moon. The Sun moves exactly that fast (on average), the stars a smidgen faster, and the Moon a tad slower. (The Moon lags behind the stars by approximately its own width every hour.)
Since Venus is never more than about $45^\circ$ from the Sun, it always sets at most 3 hours after the Sun does, and rises at most 3 hours before.