A few weeks ago, I wrote a post about Saturn’s rings, in a preemptive attempt to address some recent research that I thought some young-Earth creationists (YECs) may use to assert their views. I am somewhat surprised that the three main sources I read for creationist stuff have been silent on it. Swing and a miss on my part.
Let’s see if my fledgeling psychic powers are better-tuned for this one. This past week, several news outlets were running the story that the planet Venus may have active volcanism, revealed by the ESA spacecraft Venus Express (ESA press release, NASA press release, and Science journal article (the last one requires a paid subscription)). Seems like a possible story that a YEC may latch onto, so here’s another preemptive post explaining the science so if there is a YEC response, I can dive right into it without the background info needing to be repeated.
There is some basic information about Venus that’s relevant to this discussion. First, as most people know, Venus is the second known planet from the sun, residing about 71% as far from the sun as Earth does. Conveniently, and importantly for this post, Venus has a diameter that is 94.9% Earth’s diameter. However, since its overall density is less, its mass is 81.5% that of Earth’s.
The surface of Venus is shrouded from Earth in visible light, hidden by clouds so thick that the temperature is around 465 °C, and hence you often hear that the surface is hot enough to melt lead. The atmosphere is nearly 100 times as massive as Earth’s exerting 92 bars of pressure on the surface that is the equivalent of being under about 1 km of water. Now you may have an idea why it’s hard to build a spacecraft to land on it and survive long enough to do anything useful.
The other thing about its surface is that it has been imaged, just not in visible light. The spacecraft Magellan mapped nearly 100% of Venus’s surface and determined its topography when it orbited in 1990 through 1994. Among other things, the data showed that Venus has many volcanoes, and it only has about 1000 craters.
Now you may be wondering, “Why is he talking about craters? Is it because he studies them and just thought it would be fun to mention?” Well, yeah, I do study them, but they are also the ONLY way to tell relative geologic ages in the solar system since we lack any way to absolutely determine the ages (such as through biological means on Earth and radiometric dating on Earth and the Moon). In contrast to Venus having only 1000 craters, and nearly all of them larger than 5 km in diameter, means that Venus’ surface is very young. In contrast, the planet Mars has about 45,000 craters that are larger than 5 km in diameter.
Based on a lot of modeling, current estimates of Venus’ surface cratering age shows it to be about 700 million years old. Yes, that may seem old, but compared to the moon, Mars, and Mercury – the other large, non-Earth bodies in the inner solar system – Venus has the youngest overall surface. And the last paper to really study the distribution of craters on Venus shows that they are completely random, so it’s not just that half the planet’s surface is 1 billion years old and the other half is 500 million, but the whole surface is about 700 million years old.
The next question one may logically ask is how an entire planet with a surface area 90% that of Earth’s (95%^2) can be resurfaced? From the geologic evidence of massive volcanoes across the planet, the general consensus is that it was volcanic eruptions.
Let’s look at Venus, Earth, and Mars. Mars is only 45% the diameter of Earth, and its mass is only 10%. The analogy I like to give is that if you take a little cupcake and a big cake out of the oven at the same time, which is going to cool faster? This is why Mars has long been termed “geologically dead,” though it does show some pittance of active geology today — but none from internal heat sources.
In contrast, Earth has a lot of internal heat, and we see that every day in the form of volcanoes and undersea vents. Our heat drives plate tectonics, making earthquakes that have also been in the news a lot lately with Haiti, Chili, and Mexico. So while Earth is internally molten, our lithosphere (the region below the crust and above the mantle) is thin enough and fractured enough to let some of that heat out.
The thinking is that Venus has a lot of internal heat like Earth, but, it has a thicker lithosphere. That lithosphere under normal circumstances is simply too thick to let heat escape, so the heat stays trapped inside.
Now here’s another analogy: Let’s say you’re going to spend another lonely night in your 1-bedroom apartment, and even the cat doesn’t want to have anything to do with you. You’re going to watch a cheesy movie and don’t want to cook, so you go to the freezer and look through your few dozen frozen microwaveable dinners that you bought in bulk at Costco. You choose one and read the directions for lack of anything better to do. The directions state quite clearly: “PUNCTURE WRAPPING BEFORE MICROWAVING.” From past experience, you know that if you don’t, the heat will build up and explode in what means 10 minutes of messy clean up. But if you do puncture the wrapping, the steam can escape and it’s all good.
This is the same – albeit simplified – thing that happens with planets. Since Earth can release its heat, it doesn’t “explode.” With Venus, the thought is that since the lithosphere is thicker, the heat builds up until the molten rock finally forces its way out. When it does, the lithosphere cracks and planet-wide, catastrophic volcanism ensues. And the last time this happened – based on the craters – was around 700 million years ago.
Fascinating … What Does This Have to Do with the Press Release?
Good question, I’m glad you asked. Let’s get back on-topic. With a last massive planetary resurfacing 700 million years ago, one question has been, “Is this going to happen again?” Another is, “How often does this happen?” And the most relevant to this discussion, “Is there still some dribble of volcanism today?”
It’s that last question that Venus Express may have found evidence to answer in the affirmative. From the NASA press release: “For the first time, scientists have detected clear signs of recent lava flows on the surface of Venus. The observations reveal that volcanoes on Venus appeared to erupt between a few hundred years to 2.5 million years ago. This suggests the planet may still be geologically active, making Venus one of the few worlds in our solar system that has been volcanically active within the last 3 million years.”
I’m guessing they had to add “one of the few” because of Earth and Io.
Anyway, going off of the press release (I don’t have access to the Science article right now — I’ll update this later if needed when I get ahold of it), the researchers were able to study the mineralogy on three of Venus’ volcanoes. The mineralogy matches that on recent volcanic eruptions from some volcanoes on Earth, like Hawai’i. On Earth, the rock’s reaction with oxygen quickly changes the mineralogy, and hence the research strongly suggests that the flows are young enough to not have been modified. They suggest anywhere from a few hundred to 2.5 million years old.
This may change the picture that I outlined above of the catastrophic volcanism. In perhaps the more controversial part of the press release to me, they suggest that this could indicate the volcanism on Venus has been gradual throughout time – in a kind of steady state situation where localized events happen to resurface the area and cover a few craters, die down, and then happen elsewhere, but not covering enough to maintain the 700-million-year-old crater surface age. It’s a possibility, but at least to me they will need to show more evidence before I find it more convincing than the catastrophic scenario.
What’s this to Do with Young-Earth Creationism?
Venus has come up in the YEC literature before. I wrote one of my first blog posts on, “ Venus and the Battle of Uniformitarianism (A Creationist Argument).”
In this case, I am guessing that if some YEC person or institute chooses to use this to try to add evidence for their claims it will be along the lines of, “Since Venus has active volcanism today, it must have been created in the very recent past – 6000 years ago. Evolutionists/Darwinists/Evilutionists will have to completely change their thinking in order to reconcile an active Venus with an old-Earth.” Or something like that.
We’ll see if my budding psychic powers have been led astray again. I hope not, but we’ll see. Even if they have, hopefully I’ve given you enough information to find this press release interesting and have newfound interest in the field of planetary geology and geophysics.