Which planet is closest to Earth? Only 8% of the Danish youth can answer this correctly. Although, it actually depends on how we define it.
If we measure it in terms of distance, we get this:
– Venus: 38 million km when it’s closest, and 261 million km when its farthest away.
– Mars: 54.6 million kilometers when its closest, and 401 million km when its farthest away.
Yes, Venus is closer.
But, if we actually had to fly there with a rocket, it might be more relevant to talk about how much Delta V we would need, which is a measurement of the change in velocity we need when we navigate through space. Here the helpful graph below can give you some insight into that. And it’s actually much harder to fly to Venus than it is to fly to Mars.
So, in terms of Delta V, Mars is closer because it takes less effort to get there.
Think about it like this: Imagine that there are two candy stores near your home. One is up on the top of a large hill. The other store is just down the street. In terms of distance, the one on the top of the hill is closer, but going up all those stairs is not your idea of fun. So, you go to the one down the street.
Of course, the real reason why we are not planning to go to Venus anytime soon is because the surface temperature is about 460 degrees Celsius with an atmospheric pressure 90 times higher than here on Earth. On Mars, it’s around -55 degrees Celsius (like a very cold winter day in Alaska).