Transit of Venus
A tiny black dot on the Sun.
Bigger than the Moon
Mercury and Venus are larger than the Moon. They also pass between the Earth and the Sun.
Can Venus cover the Sun like the Moon does?
What this lesson covers
The idea
Mercury and Venus are larger than the Moon but much farther away, so their apparent sizes are too small to block the Sun; Venus passing between Sun and Earth appears as a tiny black dot, a rare Transit of Venus.
Bigger than the Moon
Mercury and Venus are larger than the Moon. They also pass between the Earth and the Sun.
Can Venus cover the Sun like the Moon does?
- No, it is too far away
- Yes, it is bigger, so it can
- Only at night
Moon or Venus?
Put each one in front of the Sun and look at the picture of the sky. These are models, not to scale.
Big, but far
Venus is larger than the Moon, but it is much farther. So it looks very small and cannot block the Sun.
Mercury and Venus are larger than the Moon but much farther away, so their apparent sizes are too small to block the Sun; Venus passing between Sun and Earth appears as a tiny black dot, a rare Transit of Venus.
Notes
Mercury and Venus are larger than the Moon but much farther away, so their apparent sizes are too small to block the Sun; Venus passing between Sun and Earth appears as a tiny black dot, a rare Transit of Venus.
Check yourself
Mercury and Venus are … the Moon, but much farther away.
Why can Venus not block the Sun?
When Venus passes between the Sun and the Earth, it looks like …
The rare event of Venus passing between the Sun and the Earth is called …
- exactly the same size as. They are larger than the Moon.
- smaller than. They are larger than the Moon.
- larger than — correct. Yes! But they are far away.
- Its apparent size is too small, because it is far away — correct. Yes! Distance makes it look tiny.
- It is smaller than the Moon. Venus is larger than the Moon. The problem is its distance.
- It is too close to the Earth. Venus is far from the Earth, not close.
- a big dark disc covering the Sun. Venus looks tiny. It cannot cover the Sun.
- a tiny black dot on the Sun — correct. Yes! It moves across the bright face of the Sun.
- a bright new star. Venus looks dark against the bright face of the Sun.
- a lunar eclipse. A lunar eclipse is the Earth’s shadow falling on the Moon.
- a solar eclipse. In a solar eclipse the Moon blocks the Sun. Venus cannot.
- a Transit of Venus — correct. Yes! It is rare.