Why Venus Remains A 'Mysterious Planet'

Venus is getting some rare attention, thanks to NASA’s Parker Solar Probe. It will swing by the planet on its way to study the sun’s atmosphere.

Here & Now‘s Peter O’Dowd talks with astronomer Dean Regas (@DeanRegas) about the NASA mission and what’s known and unknown about Venus.

Interview Highlights

On the logistics of the Parker Solar Probe's future trip to the sun, and the records the probe will break

“It's one of those things you think, ‘Alright, we’re going to fly a mission to the sun.' Now, that sounds easy in one way and hard another way. You think, ‘Alright, well, we can aim stuff at the sun. That’s easy, it’s up there, it’s big.' But the problem is, we’re going around the sun and the earth so fast — we’re going about 66, 67 thousand miles an hour around the sun — and we actually need to send a spacecraft off the earth and then slow it down so it can get closer to the sun. And so, just like you said, Venus is going to act as a break for us.

“It’s going to break all speed records ever made by any spacecraft ever, and it’s going to go to a place no other spacecraft has gone before, just about 4 million miles from the surface of the sun, and it’s all to get a little bit closer so we can go through what’s called the corona, the outer atmosphere of the sun.”

On Venus being largely ignored by scientists and the general public as a subject for exploration

“Venus has been neglected from us for a while. We had a spacecraft there called Magellan, back in the early 90s, that mapped out the planet for the first time, and [what's] so weird to think of is that here we have Venus up there, one of our closest planet that can get to the earth, and we didn’t even know what the surface of Venus looked like until 1990.

“There were no Venus globes before then. When I was growing up as a kid, we had the earth globe and maybe a little Mars, but that’s about it, and the moon.

“Then a few years ago, we had a European space agency spacecraft called the Venus Express that was there circling around the planet for a number of years, and it just recently crashed into the planet on purpose to end its mission.”

On what little we know about Venus, and how inhospitable of a planet it is

“It’s a mysterious planet, because it’s covered in clouds, so we can’t see through the clouds from ground-based telescopes. You have to really be close by to check it out. Now, it’s often called our sister planet, and I jokingly add in that it’s our twisted sister planet, because it is not really a pleasant place. This is probably the least hospitable place for us to go visit.

“[It's] 850 to 900 degrees on the planet, and there’s three ways to die on Venus real quick: One is you’re going to melt. Two, you’re going to be crushed by the atmosphere that’s pushing down on you — 92 times the atmosphere of Earth right there — and then three, if it starts raining, it doesn’t rain water. It rains sulfuric acid.

“The atmosphere of Venus is so incredibly thick and dense, and it’s mostly made of CO2, so it acts like this greenhouse gas green house gone wild.

“It’s a fascinating world, because on earth, we have very different temperatures … but on Venus, the temperature is the same on the entire planet every day. Nighttime, daytime, equator, it doesn’t matter — it’s 860 degrees.”

On the potential of Venus having a past in which it looked similar to Earth, and the planet's quirks

“We’re just kind of scratching the surface here on our understanding of it, but it’s seems that there’s a lot of evidence pointing to Venus having a very different past, that the atmosphere wasn’t as thick back then, that there could have even been liquid water on the surface.

“When we look at the surface of Venus, there’s all these, this evidence of volcanism, where there’s volcanoes and lava pools and things like that that have all become dormant, and so something has changed on that surface of Venus, and we’re not sure if that is what caused this greenhouse effect, or if it’s been for a lot longer than that. But right now, it’s looking like Venus was a more hospitable place in the past.

“It could have been a little more like Earth, of course, you know, same size, not too much closer to the sun than us. There could have been some similarities, but there is also some other weird things about Venus. It rotates backwards compared to us. It also rotates so slowly that its day is longer than its year. Now, calendars get totally crazy on Venus … It spins so slowly it takes 243 days to spin once, so that’s its day, but it takes 225 days to go around the sun, so that’s its year.

“So man, forget about your work week. Boy, I can’t wait for the weekend on Venus, that’s for sure.”

On why Mars, as a more hospitable planet, gets more attention than Venus

“I guess I like a nice planet where I can stand and live for a little bit. Venus, it’s not that we haven’t tried — that’s for sure. We’ve sent spacecraft after spacecraft to Venus. The Soviet Union sent a lot of these spacecrafts and landers, and they just kept failing and failing and landing and crashing, and the Americans would send things and they would crash.

“The longest lasting spacecraft on Venus, I think, lasted about two hours before it basically melted into a pile of goop … It’s not a place that maybe our future holds. But, there are some visionaries that think, ‘Well, maybe we can establish something in the cloud tops, that if you’re up at a higher elevation, the temperature and the pressures could be more like Earth.' But, I think you’re right, I think the future is Mars, and it’s mostly because of this idea that NASA wants to follow the water. Any place where there’s water found in the solar system, that’s the place we want to really highlight.”

On Venus's mystical qualities

“Oh, I love seeing Venus in the nighttime sky. It is the brightest star-like object, brightest planet up there, and right now, it’s in the evening sky for the next month or so. You’re going to see it every night after the sun goes down, and it’s like this suspiciously bright light, it’s almost like a UFO coming at you.

“The ancients, when they saw this, too were totally transfixed by this. That’s why it became the goddess basically, because it was so bright. So right now, it’s the evening star, visible right after dark.”

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