Question 8: the correct answer is Venus. Got it right? Score 1 point.
Question 9 of 10
Who was the first human being to go into space?
Why, in question 8: What is the hottest planet in the Solar System?
The answer is Venus. Mercury is closer to the Sun, but Venus has a dense atmosphere of carbon dioxide that traps heat. The surface exceeds 460 °C, both day and night.
A runaway greenhouse
The pressure on Venus's surface is about 90 times that of Earth, similar to what exists nearly 1 kilometer deep in the ocean.
Sulfuric acid clouds cover the entire planet and reflect much of the Sun's light. That is why Venus shines so brightly in the sky, and also why the surface cannot be seen with an ordinary telescope.
The Soviet Venera probes were the first to land on Venus and send back photos of its surface, in the 1970s. None lasted more than about two hours before being overcome by the heat and pressure.
Venus and Earth are similar in size, which is why Venus has been called Earth's sister planet. The difference in fate between the two helps scientists understand the greenhouse effect.
