Why Venus is called Earth's evil twin
Venus is the second-closest planet to the Sun, and at an average distance of 40 million kilometres from Earth, it’s our hottest, strangest neighbour.
Sometimes Venus is called things like Earth’s evil twin or Earth’s twisted sister because it’s similar to Earth in many ways. Venus is a small, rocky planet, like Earth, and it’s a similar size to Earth. But it’s also a nightmarishly hot hellscape.
Once upon a time, long ago, when the Sun was dimmer and cooler, Venus had great oceans of liquid water. As the planet heated up, the oceans evaporated into carbon dioxide, trapping more heat in a runaway greenhouse gas effect.
Despite Mercury being closer to the Sun, today, Venus is hotter than Mercury because of that thick, carbon dioxide atmosphere that’s trapping all the heat, giving the planet a near-constant toasty surface temperature of 467° Celsius.
As if it’s not enough that Venus has surface temperatures hot enough to melt lead and an atmosphere so thick it would feel like wading through soup, the atmospheric pressure on Venus is almost 100 times that of Earth.
Why is Venus called the Morning Star or the Evening Star?
Venus is a planet, that’s not in any doubt. But, since it’s a planet and not a star, why do some people call Venus the Morning Star or the Evening Star? We can thank ancient astronomers for this confusion, probably starting with the Babylonians sometime close to around 2000 BCE.
Venus’ orbit is closer to the Sun than Earth’s, and much closer than the outer planets of the solar system. This means that, for most of the year, we can’t see Venus at all because it’s too close to the Sun, only appearing above the horizon during daylight hours. But, around every 18 months, and for a few months at a time, Venus reaches its farthest point from the Sun (called its greatest elongation).
Depending on when they observed it, people saw Venus before sunrise as a bright star in the eastern sky, or after sunset as a bright star in the west. This led people to mistakenly think Venus was two different objects: a morning star and an evening star.
The Greek mathematician Pythagoras is usually credited with first recognising that the stars they called Phosphorus and Hesperus were the same object, but it’s also thought that many people might have already come to the same conclusion, since, like Superman and Clark Kent, you never saw the two together.
In the book Astronomy: Sky Country, Karlie Noon and Krystal De Napoli describe how the Yolŋu people of north-east Arnhem Land see Venus as a creator spirit. ‘Barnumbirr’, the morning star, is believed to have guided the first humans to Arnhem Land.
When can I see Venus?
In the months when you can see Venus before sunrise or after sunset, it’s visible to the naked eye for skywatchers and stargazers as the second-brightest object in the ngiht sky, after the Moon.
Venus is the biggest of all the planets when viewed through binoculars, but without some very specialist equipment, even with a telescope you will only see Venus as a featureless disk, because of its thick cloud cover.
On August 16, Venus and the Moon will appear close together in the western sky all night, until Venus drops below the horizon at 9.26pm, and the Moon follows about 15 minutes behind.
Less than a week later, on August 22, Venus reaches its highest altitude at sunset for 2026. When the Sun sets at 5.53pm, you’ll find Venus about 43° above the western horizon.
For your safety, take care to wait until after the Sun sets before looking for Venus, the best, highest view will be around 6.05pm.
If all of that isn’t enough, eager stargazers can catch Venus shining at its brightest in the evening sky about a month later, on September 23. After the Sun sets at 6.15pm, wait for the sky to become truly dark, and you’ll see Venus in the western sky.
Check out In The Sky’s table of Venus’ elongations for more data on when you’ll be able to see it from Perth.
Is there life on Venus?
The short answer to the question is there life on Venus? is almost certainly no. So why is it even a question?
In September 2020, the paper Phosphine gas in the cloud decks of Venus reported the “apparent presence of phosphine gas” in Venus’ atmosphere. Why would anyone care? Phosphine is considered by scientists to be a ‘biosignature gas.’ That is, it’s a gas often produced by living organisms.
If astrobiologists detect phosphine in a rocky exoplanet’s atmosphere, that might be a promising sign of life. After all, we think Venus once had liquid water oceans, and conditions in its atmosphere are less hellish than on the planet’s surface.
The paper was saying something like “we seem to have found signs of this gas, and we can’t yet explain it,” but news headline writers interpreted it variously as Scientists baffled after discovering gas typically found on Venus in penguin poo (which is very confusingly worded), and the more preposterous Penguins Might Be Aliens.
While follow-up research, including by the original paper’s authors, remains undecided about the presence of phosphine, the original research didn’t address whether penguins might come from Venus.
Fun facts about Venus
Venus is a great source of fun facts and possible pub trivia questions.
For example, Venus rotates backwards compared to Earth (and every other planet in our solar system). This means, if you spent a day on Venus, you would see the Sun rise in the west and set in the east.
But, Venus also rotates so slowly that a single day on Venus lasts about as long as 243 Earth days. In fact, Venus rotates at such a leisurely pace that a single day on Venus is longer than a Venusian year: the planet completes one trip around the Sun in the equivalent of around 225 Earth days.
Although conditions on the surface of Venus are the closest thing to hell imaginable, some scientists have floated the idea of permanent floating cities about fifty kilometres above the surface in Venus’ atmospheric clouds. Venus is also, on average, about 120 million kilometres closer to Earth than Mars.
Check out NASA JPL’s Visions of the Future poster for Venus to see a fanciful vision of what that cloud-life might look like.
We’re not kidding about Venus’ surface conditions, though. The Guinness World Record for Longest time survived on Venus by a spacecraft belongs to the Soviet Venera 13 lander. In March 1982, it continued transmitting data for 127 minutes after reaching the Venusian surface.
Compare that to NASA’s Opportunity rover, which operated on the surface of Mars for over 14 years.
Jay Chesters
Jay Chesters is an award-winning wordsmith and science communicator with a little bit of a thing for the stars.
A cosmic storyteller with a love for astronomy and space that's out of this world, Jay’s always eager to share his knowledge and passions.
