Similarly, we don’t see a transit of Venus every time Venus is between Earth and the Sun—which happens about every 584 days or 1.6 years. That’s because both Venus and the Moon, from our earthly point of view, can be above or below the Sun (Fig. 2), and sunlight reaches us undisturbed.

A transit of Venus across the Sun takes place when the planet Venus passes directly between the Sun and a superior planet, becoming visible against (and hence obscuring a small portion of) the solar disk. During a transit, Venus can be seen from Earth as a small black dot moving across the face of the Sun.

Venus and Mercury. Mercury and Venus, having no moons at all, never have eclipses of any kind. Observers on the searing hot surface of Venus, would never directly experience an eclipse even if the planet had a moon, simply because it is constantly enveloped by thick clouds.

Mercury and Venus do not obscure the Sun; therefore, they don’t cast the Earth into a shadow. The seemingly small planets just appear as dark spots that seem to crawl across the surface of the Sun.

Venus transits occur when Venus reaches a point in its orbit that brings the planet directly between the Earth and the sun. Since the tilt of Venus’ orbit isn’t exactly the same as that of Earth, the events are rare, occurring just four times every 243 years.

Earth

The story is about a class of students on Venus, which, in this story, is a world of constant rainstorms, where the Sun is only visible for one hour every seven years.

Most astronomers feel that it would be impossible for life to exist on Venus. Today, Venus is a very hostile place. It is a very dry planet with no evidence of water, its surface temperature is hot enough to melt lead, and its atmosphere is so thick that the air pressure on its surface is over 90 times that on Earth.

Nothing could live on what passes for land on Venus; its smooth volcanic plains are a scorching hellscape hot enough to melt lead, where the temperatures exceed 800 degrees Fahrenheit. High in the clouds, however, the pressures and temperatures and acidity levels would be less intense — though still vile.

With extreme surface temperatures reaching nearly 735 K (462 °C; 863 °F) and an atmospheric pressure 90 times that of Earth, the conditions on Venus make water-based life as we know it unlikely on the surface of the planet.

If a human lands on Venus, they already weigh 10% less than on Earth. That is 9 times the temperatures in the hottest deserts here on Earth. The heat would not destroy your suit though. The atmosphere is 96% carbon dioxide and full of sulfuric acid clouds and droplets and ash from the volcanoes that dot the surface.

0.015% 0.007% 3.5% 64% Page 2 Venus is the most dangerous planet in the solar system: its surface is at 393°C, hot enough to melt lead. It’s even hotter than the planet Mercury, which is closest to the Sun. Acting together, heat, acid, and pressure allow only the strongest spacecraft to survive on the surface of Venus.