Its hot enough on the surface of Venus to melt lead. There are also crushing surface pressures and clouds full of sulfuric acid. So theres no water on the surface of Venus today. This planet orbiting next-inward from Earth around the sun is one of the most inhospitable places in our solar system. But scientists think that, a few billion years ago, Venus might have had oceans, perhaps much like those on Earth. Venus might once have been habitable. Even now, some have suggested terraforming Venus, so that it could become a water world once again in the future. What would Venus look like with water? Reddit user Dragonite-2 has created a map, based on spacecraft data about Venus terrain, and posted it to the MapPorn subreddit. It portrays Venus if it were terraformed to become a more Earth-like world, with a similar amount of water to Earth.

The map has now gone viral.

How accurate is it? And what does it show?

Venus is covered with dense clouds. So we cant see its surface. But radar from spacecraft orbiting this world, or (in the early days) from Earth can penetrate the planets clouds and has let scientists make maps of the highs and lows on Venus surface. Thats why Venus has a known topography, which Dragonite-2 used to create his map of Venus as a water world. Radar images show us Venus mountain ranges, volcanoes, quasi-continental formations and other, flatter regions.

Thus, weve known and now Dragonite-2 has helped us see that if Venus had an Earth-like quantity of water, it would have one large continent in its northern hemisphere. Scientists have named this continent already; they call it Ishtar Terra. Its about the size of Australia. The highest point on Venus, the mountain Maxwell Montes, is located on Ishtar Terra. Theres also a second large continent which scientists call Aphrodite Terra located along the equator of Venus. Its the size of South America (if South America were stretched out along Earths equator, instead of running perpendicular to it). Dragonite-2s map also illustrates smaller continents and islands that would be scattered throughout Venus global oceans, if Venus were a water world.

Dragonite-2s map posted to Reddit is based on spacecraft data. Most of our information about what lies beneath the dense clouds of Venus was obtained by the Soviet space probe missions Venera 15 and 16 and by the American Pioneer Venus and Magellan spacecraft during the period 1978 to 1994. Today we have good information about 98% of the surface of Venus, according to this page from ESO. This map comes from NOAAs Science on a Sphere. Its a compilation of Venus radar data, showing Venus topography as its known today. NOAA wrote: Most of Venus appears to be covered with gently rolling plains. Two areas rise up above the rest of the surface and are referred to as continents.'

Writing in Inverse on August 29, 2020, Mike Brown described the new Venus-as-water-world map. He quoted an associate professor of planetary sciences at North Carolina State University Paul Byrne who told Brown that, in one sense, the map is fairly accurate:

in that someone has taken the real-world digital elevation model for Venus and added a sea level to it.

I dont know how realistic the if Venus had as much water as Earth part is, but Im guessing that whoever made this map picked an average ocean depth for Earth and flooded the Venus topography to that same depth.

However, as Byrne also noted to Brown, the surface would look quite different after erosion by rainfall, rivers and lakes. The map portrays Venus surface as-is, without plate tectonics. But a planet with oceans likely would have plate tectonics the gradual movement of land plates on the planets crust, relative to one another just as Earth does.

And that movement of crustal plates would, of course, affect the configuration of continents and islands.

Venus as seen in enhanced color by Japans Akatsuki spacecraft. Its surface cannot be seen with the eye alone. Its completely covered with dense clouds. Theres a wonderful article about real images of Venus via Japans Akatsuki spacecraft, at the Planetary Society blog. Akatsuki began orbiting Venus in 2015. The images were put through special processing and released in 2018.

Artists concept of what a terraformed Venus might look like, with Earth-like oceans, continents and clouds. Image via Ittiz/ Wikimedia Commons.

But, of course, in another sense, the map of Venus as a water world doesnt compute under current real-world conditions. As planetary scientist Byrne noted in the Inverse article:

In reality, its not remotely realistic.

Thats because of the extreme conditions that exist on Venus today. A watery ocean cant exist on a world thats hot enough to melt lead. So the map isnt accurate in terms of the real planet Venus now. And now is what this map shows. See the contradiction?

Still, Dragonite-2s map helps us use our imaginations and cast our minds back in time or forward into the future when, according to some visionaries, Venus might be a very different place. Byrne was speaking of the past Venus when he said:

Although a Venus with oceans wouldnt look much like the Reddit image, it is fun to think about what a blue Venus might once have looked like, and why its climate turned into the hellish world it is today.

And we can imagine Venus as a terraformed world, purposely made to be more habitable and Earth-like again. This is a well-known concept for Mars, to transform the dry, cold planet back into a habitable one. Despite the fact that Mars is the most Earthlike world in our solar system, terraforming Mars would be difficult, according to most experts.

But terraforming Venus a world the same size and density as Earth, but not remotely like Earth on its surface would be even more difficult.

That hasnt stopped some people from thinking about it, though. The famed astronomer Carl Sagan was one of the first to propose ways to terraform Venus, back in 1961. Sagan had suggested seeding Venus clouds with algae; later, it was determined that wouldnt work because the atmosphere was found to be too thick. Astronomer Geoffrey Landis mentioned Sagans ideas, and the history of terraforming in general, in a paper from 2011.

Below is a short video animation depicting how the surface of Venus might look during a gradual transformation back into a water world:

Of course, the biggest hurdle in terraforming Venus would be in trying to reverse the runaway greenhouse effect that caused the planet to heat up to the extreme temperatures we see today. That wouldnt be easy. It would require huge amounts of energy and advanced technology. But a terraformed Venus might have some advantages over a terraformed Mars, according to Paul Byrne. As Byrne points out, Venus is almost the same size as Earth, with similar gravity, and it might be easier to remove carbon dioxide which makes up most of the planets atmosphere and causes the greenhouse effect from its atmosphere to cool the planet, than to add gases to Mars thin atmosphere to warm it. Byrne commented:

If we were to terraform anywhere, then Id pick Venus over Mars. But, to be clear: its going to be orders of magnitude more achievable to stop f%#&ing up our own climate here on Earth than trying to make anywhere else even remotely habitable for humans.

Good point.

So while Dragonite-2s map in Reddit might not be all that accurate according to scientists it does give us a reason to think. It provides an interesting glimpse at Venus as weve never known it, but which might have existed in the past. And just maybe it gives us a vision a world that might exist again in the future.

Not ready to stop thinking about maps and worlds made habitable via terraforming? Dragonite-2 posted another imaginary water-world map on the subreddit MapPorn, a few days after the Venus map. Its shared below. It shows what Earths moon would look like, if it were covered with water. Enjoy!

Another great map that depicts the moon if its had as much water as Earth from r/MapPorn

Bottom line: A cool new map by a Reddit user shows what Venus might look like with oceans on its surface.

Via Reddits MapPorn

Via Inverse

Via NOAAs Science on a Sphere

Read more:

Cool! Heres how Venus would look as a water world - EarthSky