NeoScience Daily · SUN 25 OCT 2026 · Issue 02

Venus comes close, and you should not answer the door

It swings in closer than you'd like, most of its ground is volcanic flow and it crosses the Sun on a schedule you'll probably miss, which, fine, none of that was for you anyway.

Why care about Earth's evil twin?

Venus is the brightest thing in the night sky after the Moon, it's named after the goddess of love, and for centuries people wrote poems about it. It's also the most hostile place any machine has ever landed, a planet so hot that lead would run like water across the ground, under air so heavy it crushes spacecraft like soda cans, beneath clouds of sulfuric acid. So why should you and I give a damn about the one planet that would kill you faster than almost anywhere else?

Here's why: Venus is the same size as Earth. It's almost the same mass, it's made of about the same stuff, and it sits right next door. If you were an alien looking at our solar system from far away and trying to pick out which planet had life on it, you might well pick Venus. And yet one of these two worlds grew oceans, forests and people who complain about parking, and the other one turned into hell with a nice view. Nobody can tell you for sure why, and that's a bit of a problem, because we happen to live on the other one.

Venus has no interest in helping us figure it out. It sits about 67 million miles from the Sun, turning backwards at about walking pace, and it hasn't noticed we're here. It's been called Earth's twin for so long that people forget the rest of the family story: one twin got into medical school and the other burned the house down.

So that's what this issue is about: why on earth you and I should care about our evil twin, and why we maybe shouldn't. Along the way we'll get into how a planet goes from possibly having oceans to melting lead, why it takes longer to spin once than to go around the Sun, the Soviet robots that landed there and died within hours, the strange idea that people could one day live in its clouds, and whether Venus is a warning we should actually be listening to, or just the prettiest death trap in the sky.

But first you need to know where Venus lives, because on paper it has the best address in the solar system.

Venus in pictures

CLOUD TOPS In February 1974, NASA's Mariner 10 spacecraft sped away from Venus and captured a seemingly peaceful view. Galileo first observed the phases of Venus through his telescope, and the planet's discovery date is listed as prehistoric.

MOUNTAINS AND LOWLANDS Maxwell Montes, the highest point on the planet, is elevated more than 6.2 miles above the surrounding lowlands. Yet over 80% of Venus lies within 0.62 miles of the mean radius of 3,760 miles, so most of the planet sits close to one level. At least 85% of the surface is covered with volcanic flows, the remainder by highly deformed mountain belts.

RADAR MAPS NASA's Magellan spacecraft ended a five-year mission to Venus in 1994. It mapped the broiling surface using radar. Across the equator, Venus is slightly smaller than Earth: about 7,521 miles against 7,926 miles.

PROBES BELOW THE CLOUDS Some of the Russian Venera probes detected particles about 0.00004 inches in length in the lower atmosphere. They belonged to the Soviet Union's Venera program. Among the survivors, the shortest lasted 23 minutes.

The twin next door

Venus is second in line from the Sun, about 67 million miles out, roughly 70 percent of Earth's distance. It's also the closest any planet ever gets to us, coming within about 24 million miles, so if you ever wanted to borrow a cup of sugar, this is the neighbor you'd try, assuming you hadn't heard the stories.

On paper the two of us look like a matched set. Venus is about 7,520 miles wide, 95 percent of Earth's width, and it has about 82 percent of our mass, so its gravity is about 90 percent of what you feel right now. You could walk around on Venus and feel almost normal, for the fraction of a second you had left. It's rocky, it has an iron core, it has volcanoes, and it even has an atmosphere. And then you go outside.

The air on Venus is about 96 percent carbon dioxide, and there's a ridiculous amount of it. At the surface the pressure is about 92 times what you're feeling now, the same as being 3,000 feet underwater, deep enough to crush a lot of submarines. The temperature down there is about 869 °F, day and night, at the equator and at the poles, in every season, because all that air spreads the heat around like a giant oven with the fan on. That makes Venus hotter than Mercury, even though Mercury is roughly twice as close to the Sun, and that should tell you something about how much trouble you can get into with the wrong atmosphere.

Then there are the clouds. They're a thick layer of sulfuric acid droplets about 31 to 43 miles up, they cover the entire planet all the time, and they reflect around three quarters of the sunlight that hits them, which is exactly why Venus looks so bright and lovely from here. So the prettiest thing in the night sky is pretty because it's wrapped in battery acid. There's a dating lesson in there somewhere.

Venus also refuses to move like anything else in the solar system. It spins backwards compared with almost every other planet, so if you could see the Sun from its surface, which you can't, it would rise in the west and set in the east. And it can barely be bothered to do even that, taking about 243 of our days to turn once, while only needing about 225 to go around the Sun. So one Venus spin takes longer than a Venus year, and your birthday would come around before the planet got all the way around. Nobody knows for sure why it spins this way, though a giant collision early on is one suggestion, and the pull of the Sun on all that thick air may have played a part too.

And here's the weird part: while the ground is barely turning, the upper atmosphere is screaming around the planet in about four days, 60 times faster than the planet beneath it. That's called super-rotation, and even today nobody has a fully satisfying explanation for how it keeps going. So the rock moves at walking pace, the wind at the top goes about as fast as a Formula 1 car flat out, and the air at the bottom just sits on you like a parked truck.

So how did the twin next door end up like this? That's the most important question in this issue, and the short version is that nobody knew any of it until very recently. For a long time, people thought Venus was paradise.

Four small facts about Venus.

Love, lies and a lot of fog

Nobody discovered Venus. It's so bright that you can see it in the daytime if you know where to look, and it's been in human records for at least about 3,600 years, since Babylonian astronomers wrote down its risings and settings on clay tablets. Like the Greeks with Mercury, a lot of ancient people first took it for two different objects, a morning star and an evening star, before working out that it was one planet. Then the Romans named it after their goddess of love, so we've been getting this planet wrong from the very start.

The first time Venus really changed anything was in 1610, when Galileo pointed his new telescope at it and saw that it goes through phases, just like the Moon, from a thin crescent to almost a full disc. That sounds like a small thing, except the only way Venus can show a full set of phases is if it goes around the Sun, which sank the old model the Catholic Church leaned on, where everything goes around the Earth. So Venus helped hand Galileo the evidence, and he then got himself sentenced to house arrest for the rest of his life, which is the kind of thanks you get for checking.

Then Venus helped us measure the solar system. In the 1700s astronomers realized that when Venus crosses the face of the Sun, which only happens in pairs about once a century, people watching from different places on Earth would see it cross at slightly different times, and that tiny difference could give you the actual distance to the Sun. So in 1761 and 1769 countries sent people all over the world to watch it, in one of the first big international science projects in history, and those people sailed off into wars, shipwrecks and tropical disease to time a dot. Captain James Cook's first voyage, the famous one, was officially sent to Tahiti to time Venus crossing the Sun in 1769. A French astronomer named Guillaume Le Gentil spent about eleven years away trying to catch both transits, missed the first because he was on a ship and missed the second because of a cloud, then got home to find he'd been declared dead and his relatives had split up his estate. So the next time your flight gets delayed, at least nobody's divided up your stuff.

During that same 1761 transit, a Russian scientist named Mikhail Lomonosov saw a blurry ring of light around Venus as it touched the Sun, and he is usually credited with working out that it had an atmosphere. And since all anyone could see through a telescope was bright, featureless cloud, and since Venus was the same size as Earth, people started filling in the blanks. By the early 1900s it was common to imagine a warm, wet Venus under those clouds, a planet of swamps and maybe even dinosaurs. Plenty of science fiction was set there. We just couldn't see the ground, so we drew whatever we wanted on it, which is what we always do.

The swamp lasted until 1962, when NASA's Mariner 2 flew past Venus, the first spacecraft ever to successfully visit another planet, and measured a surface temperature that killed the dream on the spot. A young astronomer named Carl Sagan had already argued a couple of years earlier that all that carbon dioxide might be trapping heat in a runaway greenhouse, and Mariner 2 backed him up. Earth's cuddly twin turned out to be hot enough to melt lead.

Which, of course, made a certain country want to land on it.

Galileo and the phases

Galileo Galilei (1564 to 1642). Galileo Galilei observed that Venus shows phases, similar to those of Earth's Moon. That was evidence that Venus orbited the sun, and it helped end the centuries-old belief that the sun and planets revolved around Earth.

How Venus kills you, and everything else

So let's say you're stubborn, you come down through the clouds anyway, and you reach for the door.

You don't get to open it, because it's being crushed. The pressure at the surface is about 92 times Earth's, so anything hollow that isn't built like a deep-sea submersible folds up immediately. A person would be flattened. On the way down you'd have fallen through clouds of sulfuric acid, which is the stuff in car batteries, and that would have gone to work on your suit and then on you. And then there's the heat, 869 °F, more than hot enough to melt lead, tin and zinc, which is way past what your oven manages on its highest baking setting. So you're being crushed, cooked and dissolved, and honestly it's a race to see which one gets there first.

If you somehow survived all that, you'd want to breathe, and you can't. The air is carbon dioxide with some nitrogen and traces of sulfur compounds, and it's so thick it behaves a bit like a liquid. Walking through it would feel like wading through a swimming pool, except that this is the one pool where the lifeguard is also trying to kill you. And if you were hoping for a drink to go with all this, Venus is one of the driest places we know of, with about a hundred thousand times less water in its air than Earth has in its oceans.

And the view is orange, because the thick air filters out the blue, and it's dim, like a very overcast day, since only a small fraction of the sunlight reaches the ground. So you've been crushed, boiled and dissolved, and the lighting's terrible.

Machines don't do much better, since most electronics give up not long past 257 °F, so anything we land there is just a box waiting for the oven to get to it. Which brings us to the most impressive robots you've probably never heard of.

Venus seen by probes

The spacecraft and instruments that have looked at Venus, from the early fly-by probes to a solar mission.

Magellan mapped the surface with radar NASA's Magellan spacecraft ended a five-year mission to Venus in 1994. Radar let it map the broiling surface.

Mariner 10 and its peaceful view In February 1974 NASA's Mariner 10 spacecraft sped away from Venus. As it left, it captured a view of the planet that looks seemingly peaceful.

Venera: probes to the surface The Soviet Union sent a series of probes to Venus between 1961 and 1984 as part of its Venera program. Ten probes made it to the surface, and a few functioned briefly after landing.

Parker Solar Probe and WISPR The WISPR instrument on the Parker Solar Probe is a pair of broadband optical telescopes, WISPR-I and WISPR-O. It imaged Venus during flybys on 2020 July 11 and 2021 February 20.

Mariner 2 found a dense cloud layer that extended from 35 to 50 miles above the surface.

The Soviet robots that flew into the furnace on purpose

The Soviet Union decided Venus was theirs, and for about 20 years they just kept throwing spacecraft at it. A lot of them failed. Their first few probes got crushed on the way down, because nobody knew how thick the air was until they'd lost the machines finding out, so they kept building them tougher, and they kept going, which is about the most Soviet approach to a problem I can imagine.

In 1970 Venera 7 became the first spacecraft ever to land on another planet and send a signal back. It hit the ground hard, tipped over and transmitted a faint signal for about 23 minutes, and engineers nearly missed it. So the first message ever sent from the surface of another planet was basically a very weak "ow". In 1975 Venera 9 sent back the first picture ever taken from the surface of another planet, showing flat rocks under a dim sky, and it lasted about 53 minutes.

The record holder came in 1982. Venera 13 landed, drilled a soil sample, took some of the only color pictures we have of the surface of Venus, recorded sound, and survived for 127 minutes in a place where it was only built to last 32. It managed that the same way the others did, by being chilled before the drop and soaking up heat in a block of salt, like putting a thermos in the freezer before a trip to the sauna, and when the cold ran out, so did it. Nobody has landed on Venus since 1985, which is over 40 years. In that time we've put car-sized robots and a helicopter on Mars, while the record for staying alive on Venus is still about two hours, set by a Soviet machine older than most people reading this.

Going around Venus has been easier. NASA's Magellan spacecraft used radar to see straight through the clouds from 1990 to 1994 and mapped about 98 percent of the surface. It found a planet covered in volcanoes, more than any other planet in the solar system, and a strangely young surface, maybe about 500 million years old on average, which suggests something repaved the whole planet not that long ago. In 2023, scientists going back through Magellan's old images spotted a volcanic vent that appeared to change shape between February and October 1991, which makes it the best direct evidence yet that Venus is still erupting today. So our twin is still active, it's right next door, and we mostly stopped looking.

Now we might finally go back. NASA has two missions on the books, DAVINCI, which would drop a probe through the air, and VERITAS, which would map the surface in much better detail, and Europe has one called EnVision. Congress saved the two NASA missions from proposed cancellation, and they're now aimed at about 2030 and 2032, with EnVision around 2032, however those dates have been pushed around so many times that nobody should book a hotel, so Venus remains the planet everybody means to get back to, like that friend you keep saying you'll call.

So what did all those crushed robots actually buy us? A pretty good idea of how Earth's twin went bad, and that's the part you should care about.

A fresh look at Venus' surface

EARLY SCANS Mariner 2 scanned Venus for 42 minutes. The data it returned implied no significant difference in temperature across the planet. It also found a dense cloud layer that extended from 35 to 50 miles above the surface.

VISITORS FROM THE SOVIET UNION The Soviet Union sent a series of probes between 1961 and 1984. Ten made it to the surface. The longest survivor lasted two hours. As the new views play, hold them up against that older record of scans and short visits.

Why we are going back to Venus

MISSIONS ON THE WAY David Grinspoon, who sits on the science team of NASA's DAVINCI mission, tells the hosts that Venus finally has several missions in the works. VERITAS is an orbiter that complements DAVINCI, which is an entry probe. He adds that a European mission and a possible Indian one mean many agencies are now getting into the game.

A HARD DROP Grinspoon calls the engineering of DAVINCI a real challenge. The probe must fall through clouds of concentrated acid, into growing heat and crushing pressure, and still keep working. He says much of it is already built, including the entry sphere and some of the instruments, and that Congress has been supportive.

PHOTOGRAPHING THE DESCENT Beyond measuring gases and isotopes that no modern instrument has measured in this atmosphere, DAVINCI will take pictures on the way down. Grinspoon compares it to the old Ranger images of the Moon, which grew sharper as the spacecraft closed in, but this time with modern cameras over a mountainous region.

LIFE IN THE CLOUDS Asked whether life could live in the atmosphere alone, Grinspoon says he has been a proponent of the idea. His answer to a colleague who asks why Earth's clouds are not green is that clouds on Earth come and go, while the clouds of Venus form a lasting layer, a bit like the oceans of Earth in their stability.

How a planet goes wrong

Here's the story as best we can piece it together, and a lot of it is still being argued about.

Young Venus and young Earth started out similar. The Sun was dimmer back then, and some computer models suggest Venus could have had shallow oceans and a mild climate for maybe a couple of billion years, while other models say it was always too hot for water to ever settle at all. We genuinely don't know, and the only way to find out is to go and look at the rocks, which is hard to do when they're at 869 °F.

What we do know is how the end goes. It's called a runaway greenhouse. Carbon dioxide and water vapor both trap heat, the same way a car's windows do on a sunny day. On Venus, however it started, the planet got warm enough that any water boiled into the air, and water vapor is a powerful greenhouse gas, so that made it hotter still, which boiled off more water, which made it hotter still. There's no thermostat in that loop. High up in the atmosphere, sunlight broke the water molecules apart, the hydrogen escaped into space and was gone for good, and the planet's water went with it. We can still see the fingerprint of that loss in the chemistry of the air Venus has left.

On Earth, carbon dioxide gets pulled out of the air, dissolved in the oceans, and locked into rock like limestone, and plate tectonics recycles it over millions of years. That's our thermostat. Venus lost its water, and without water that process stops, so every bit of carbon dioxide its volcanoes burped out just stayed in the air. Here's the bit that should stick with you: Earth has roughly as much carbon dioxide as Venus does. Ours is mostly locked up in rock. Theirs is in the sky.

So a lot of the difference between your planet and that one comes down to where the carbon went. Now, before anyone panics, this isn't a forecast. Scientists don't expect anything we're doing today to set off a Venus-style runaway, and burning every drop of fuel we've got is very unlikely to get us there. What Venus does show you is that a rocky planet's climate isn't guaranteed, and that one with almost the same ingredients as ours can end up like this. The Sun is also slowly getting brighter, and in somewhere around a billion years that alone could push Earth down the same road, with or without our help, so enjoy the weather while you can.

Now, you'd assume nothing could live through all that, and in 2020 a team reported finding phosphine in Venus's clouds, a gas that on Earth is mostly made by living things, and for a few weeks everyone lost their minds. Later analysis cast serious doubt on the measurement, people are still fighting about it today, and most scientists don't think it's solid evidence of anything yet. It did get everyone looking at the clouds again, however, and the clouds turn out to be the most surprising place on Venus.

Why Venus is so hot

Venus is the hottest planet because of its thick atmosphere, and in the clouds that same atmosphere is far milder than at the surface.

A greenhouse that ran away A runaway greenhouse effect traps heat in the thick atmosphere. That makes Venus the hottest planet in the solar system, hot enough to melt lead, at about 872 degrees Fahrenheit.

Milder air in the clouds About 31 miles up (about 31 miles), temperatures range from 86 to 158 Fahrenheit. That is far milder than the surface.

The gases that fill it The major gases are carbon dioxide (CO2) at 96.5% and nitrogen (N2) at 3.5%.

Cities in the clouds

Here's a fact that sounds made up: about 31 miles above the surface of Venus, the conditions are the most Earth-like anywhere in the solar system outside Earth. The pressure is about the same as sea level here, around 1 atmosphere. The temperature is somewhere between about 86 and 160 °F depending on how high you go, so you can pick your weather by picking your altitude. The gravity is about 90 percent of what you're used to, which is a much better deal for your bones than Mars's 38 percent. There's even some protection from radiation, since you've still got a thick blanket of air above you.

And here's the part that makes engineers grin. The air you and I breathe, oxygen and nitrogen, is lighter than carbon dioxide, so on Venus, breathable air is a lifting gas. A big balloon filled with plain air would just float at about the right height, the same way helium floats here, and you could live inside the thing that's holding you up. NASA engineers actually sketched this out in a concept study called HAVOC around 2015, starting with robots and working up to crews of people in airships, floating around Venus in about four days with the wind. It's the kind of idea that sounds insane until you compare it with living in a buried can on Mars.

That being said, it's still Venus. Those clouds are sulfuric acid, so everything on the outside has to be acid-proof, although a leak wouldn't be a catastrophe, since at that height the pressure's about the same inside and out, so a tear would slowly mix the air instead of blowing you out into the sky. There's also no ground to stand on, no solid rock to mine and very little water, and if your balloon ever does give out, you've got a 31-mile fall into an oven, which at least gives you time to think about your choices. Nobody is actually building this. It's a sketch on paper, and no space agency has a plan to fund it.

No Venus print yet.

NeoPrint makes custom 3D printed objects. This is what the store lists today.

NeoPrint has no Venus print or kit yet. Its store today lists 7 objects in the Moon Collection, shown as concepts, plus the Fossil Collection and a Make Your Own page. None of them is a Venus product, so there is nothing to buy for this issue.

Visit the NeoPrint store

What Venus actually offers you and me

So strip off all the romance, and here's what Venus actually has to offer.

Mostly, it's a warning label. Venus is the only Earth-sized planet gone wrong that we can actually go and study, so everything we think we know about why Earth stayed livable, the oceans, the moving plates, the carbon buried in rock, gets tested against the one world that went the other way. If you wanted one reason to spend money on Venus, that's the one.

That warning label also works as a map. Astronomers have found thousands of planets around other stars, and plenty of them are about Earth's size, however from that distance a real Earth and a Venus can look an awful lot alike, and you'd really like to know which one you're pointing at before you throw a party. The only way to learn how to tell them apart is to understand the one Venus we can reach.

Then there are the clouds. If you were serious about living off Earth, that band of air at 31 miles is one of the few places in the solar system that might keep a person's bones healthy for the long term, though nobody knows how you'd keep it fed.

It's also close. It takes less time to get to Venus than to Mars, about four to five months on a good route, with launch windows every 19 months or so instead of Mars's 26. You'd be dead sooner, but you'd get there faster.

Now the honest limits, because nothing about living on Venus is easy and none of it is being funded. There's no surface you can use, hardly any water, and every part of your home has to survive acid. You also can't get back off it easily: leaving Venus takes nearly as much energy as leaving Earth, since its gravity is about the same. Mars is a place you could visit and come home from. On Venus you'd better really like the balloon.

So, should you and I care about Venus?

Venus doesn't care about us. It's going to go on rotating backwards at walking pace under its acid clouds, crushing whatever we send it, whether or not we ever figure out what happened there.

It's the closest thing we've got to a twin, and it's hell, and nobody can say for sure how far apart our two stories really were. That being said, it's the single best teacher we've got on how a planet like ours stays livable, or stops.

So yeah, give a damn, a healthy, slightly nervous one. You don't have to want to live there. You just have to look up at that beautiful bright dot some evening, remember what's under the clouds, and be quietly glad that most of our carbon is still in the rocks.

Next time, the daily updates take one piece of this and go all the way in. We'll ride down through the acid with Venera 13, chase a volcano that may be erupting right now, and spend a day floating in a balloon 31 miles above the worst surface in the solar system.

What stuck?

  1. Venus is about twice as far from the Sun as Mercury is, so why is it hotter?
  2. What is odd about how Venus spins compared with how it orbits?
  3. What did Galileo's view of Venus going through phases prove?
  4. How did Venera 13 survive for 127 minutes when it was only built to last 32?
  5. What kept making Venus hotter once its water began to boil into the air?
  6. Why could a balloon filled with plain breathable air float in Venus's clouds?

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