AI takes weather forecasting by storm, and crabs use aspirin

Space scientists at the University of Cambridge have, they think, answered a long-standing question about our near-neighbour, Venus:  whilst it’s a hothouse today with a surface temperature sufficient to melt lead and sulphuric acid for rain, given its similarity to Earth, was it once a lot wetter, like we are? By looking at the gases that the Venusian volcanoes release, Tereza Constantinou has been able to work out how much water is really there inside the planet. And the picture it paints is not of a once watery world…

Tereza - Earth and Venus are often thought of as sister planets. That's because they're very similar in mass, radius, density and distance from the sun. But now, they've ended up looking really, really different. You've got Earth, where we've got oceans, we've got a nice climate, it's quite comfortable. However, on Venus, the surface conditions are extreme. You've got an atmospheric pressure at 90 bar, so that is 90 times the pressure that you experience when you're standing on earth, and that is the equivalent of being about a kilometre underwater. Imagine the pressure you'd feel in your ears from that, that is extreme. Then you've got the toxic atmosphere made of carbon dioxide and you've got sulphuric acid clouds. So this is vastly different from what it would be like on Earth. However, there's been this theory suggesting that Venus was once very much like Earth: it had oceans, a cool, temperate climate, but that is really unknown. Even scientists are still debating to this day whether that was the case. That's what we were seeking out to answer, trying to see if there's any evidence in what Venus looks like today that speaks to the climate past, that tells us whether Venus ever had oceans.

Chris - We struggled to do something similar for our own planet, that we are on, that's a lot less inhospitable. So how can you get to the bottom of those questions on Venus?

Tereza - It has been very tricky so far. The way it's been done for Venus is using climate modelling. That's very much what people would use when you're checking the weather for here on Earth, but doing that for an early Venus: seeing if it was ever cool and temperate, cold enough essentially to have liquid water at its surface. But we wanted to approach the problem a slightly different way. We wanted a more direct test, something to do with what Venus is like today. That is a very clear clue as to whether the past of Venus ever had oceans.

Chris - It's almost like, you know where we are today, you're going to wind the clock back using some kind of model of how things evolve and change to work out what it would've been like back in the day?

Tereza - That's essentially what has been done so far. But we wanted to do something else. We wanted to see if there was any clue within Venus as it is today that was a signature of this past. Essentially, we wanted to see if Venus in its present day has any clues about it ever having oceans. So, for example, on Mars, just by looking at the surface, you can see where water has shaped surface features. So, much like flowing water through soil or sand will shape channels and valleys, we see that on Mars. However, Venus's surface is really young in geological terms, even though it's a few hundred million years old. But essentially there was a large volcanic event that released lots of lava, covering most of the planet's surface, so if there was any evidence of flowing of water - like valleys - it is now covered, so completely erased. We've had to come up with entirely different ways to figure this out. Different clues to look for.

Chris - And what are they? How do you do it?

Tereza - The way we did it is we looked into volcanism on Venus to find out how much water is inside the planet. Now this is a very key clue to whether Venus ever had any oceans in its past. Studying the composition of the gases being released by volcanoes on Venus, we can see how much water is inside the planet. Now imagine a volcanic eruption here on earth. If you've ever seen any photos of them, you essentially see these large billowing clouds coming out. Most of that is water, and this is directly coming from the inside of the planet where the lava comes from. We wanted to do the same for Venus by studying the position of the gases coming out of Venus's clouds. We wanted to see if there was any water, or rather how much water there is inside the planets and this was a very key signature about the climate's past.

Chris - How are you actually making those measurements though?

Tereza - It would be great if we could send a probe now and study Venus's clouds, and there are plans in the future. There are probes being sent to Venus to do that, but obviously we haven't done that yet. In fact, any probes that we sent in the past died when they reached the surface due to the extreme pressures and temperatures. So we did it slightly differently. Most of the data that we have about Venus or the thing we understand the most about Venus is its atmospheric composition. So we modelled that atmospheric composition. We studied the chemistry of the atmosphere, and we looked at different gases being destroyed in the atmosphere through chemistry, which must be restored by volcanism to maintain atmospheric stability. So we use that to kind of study what kind of gas you would need to be added into the atmosphere to sustain what it is like today.

Chris - So you can basically see the atmosphere from far away. You don't need a probe to do that, and you can work out what's in it and therefore you can work out what must be going into it and what's coming out of it. So therefore you get that dynamic of what the volcanoes must be doing and therefore the amount of water can be inferred indirectly.

Tereza - Exactly. So we've been observing Venus for decades now. We've sent missions there that took some measurements of what the atmospheric composition is, and we've also used telescopes on the ground here on Earth to observe Venus and, again, study the composition of the atmosphere. That's exactly what we've used.

Chris - What does that reveal then? Is it much wetter like the Earth is, or were we wrong?

Tereza - It is really, really dry. There is so little water coming out of the volcanoes on Venus, and this is vastly different to Earth where you've got lots of water. Most of the gases released from the volcanoes are water. But that's not what we found for Venus. In fact, there was very little water, meaning the planet itself has very little water as a whole.

Chris - How do you reconcile that? Because you mentioned when you started you said, 'look, Venus is almost a sister planet to the Earth. There are so many similarities and we know the Earth's got loads of water. It had some to start with, loads of asteroids and comets rained down on it when it was young and they put water here.' Why wasn't the same happening to Venus then?

Tereza - I think Venus ended up being too close to the sun so that it took too long to cool down and solidify into this rocky body that we now know. All the water that the planet might have had only remained as steam in the atmosphere. This gave the water enough time to be dissociated. So this meant incoming radiation from the sun was strong enough to be able to break apart molecules in the atmosphere. Water was broken up into hydrogen and oxygen. Given Venus is closer to the sun, it's got more incoming radiation, and hydrogen is a very light molecule. It escapes your atmosphere at very high rates. Now, if the planet never cooled down fast enough to condense that water and trap it within your system, the water will be exposed to the sun in the atmosphere. It would dissociate and leave the planet, leaving behind a very dry and desiccated planet.

Anyone who’s ever felt a twinge of disquiet when they selected a lobster and watched it being dropped into a pan of boiling water should perhaps trust their instincts: because scientists have discovered crustaceans do appear to perceive pain. Eleftherios Kasiouras from the University of Gothenburg has found that crabs dabbed on their sensitive parts with strong vinegar will administer aspirin in the aftermath to ease the discomfort, suggesting they really are feeling pain…

Eleftherios - There are some criteria that need to be fulfilled so we're certain, and we can say beyond reasonable doubt, that crustaceans, they experience pain.

Chris - Pain is a difficult one though, isn't it? Because it's a perception. I can define pain, I can say I'm experiencing pain and you'll know exactly what I'm talking about. But how do we know that other animals share that visceral experience or whether it's just an automatic reflex for them and they don't experience the same emotional effect that we do?

Eleftherios - So we worked on shore crabs and we used different stimuli on the soft tissues of the body, like the legs, the claws, eyes and antenna, which are the little pointy things. We stimulated with acidic acid, vinegar, and it's painful to these animals, and we also used mechanical pressure to see how they responded to that. From these two different stimuli and the responses that we got in the nervous system, we could see that the signal transfers through the body to the brain and a response arises and we record these responses.

Chris - So you can demonstrate that they have the neurological capacity to detect a stimulus that we would regard as painful, and it changes brain activity when you put that stimulus into the nervous system. So you're two thirds of the way to showing that they are experiencing pain, how do we then clinch it to get the final tick in the box that this is then registering in their brain as an unpleasant thing in a way that we would say, well, that looks like they're feeling pain.

Eleftherios - We want to inflict pain on them and see how their behaviour will change and then, if we provide drugs such as analgesics, aspirin, if they would prefer the aspirin than the pain stimulus, or they want to go to the aspirin to relieve themselves from pain, that behaviour will tell us that they actually want to avoid the stimulus no matter what so they don't experience that. That's the last step of my PhD to see how the behaviour and learning come into play. That has not been answered yet, but I'm working on that.

Chris - So crabs can take aspirin. Really?

Eleftherios - Yeah. So far we've tried it on lobsters and it seemed to work okay. But more to come about that in the next paper that I'm trying to publish.

Chris - Summarising then, you stimulate them with something we would regard as painful. They flinch effectively. It's like me touching a hot plate. You can then show that they will actively seek out pain relief off the back of that with things like aspirin, which would suggest that it's an ongoing discomfort for them and they're alleviating it.

Eleftherios - Exactly. That's the next step for my experiments.

Chris - Well, what are the implications of this then? Because we traditionally just get crustaceans like crabs and we dump them in pots of boiling water to cook them. Does this mean that we ought to be rethinking this?

Eleftherios - I think so too. The industry also needs to rethink that as we do as scientists when we use them in the lab. Firstly, it's important to find methods to kill them as fast as possible. Then, for distribution we should probably be transporting dead crustaceans and not alive ones. If they're alive, the restaurants or the people that want to kill them should use methods to kill them fast when we catch them. They should be dead when we buy them from the shops.

Chris - What's a good way to do that then? Not that there's a good way to kill anything, but when it's a necessity, is cold temperature, do you think, possibly putting them in the freezer to drop the temperature down so they effectively become hypothermic and unconscious, is that the best way?

Eleftherios - We tried ice slurry because we're on the verge of finding the best method and we're conducting experiments on that. Coal doesn't seem to do the trick, especially on large lobsters. We study Norway lobsters, langoustine, and they didn't die as fast even in the freezer in minus 20. So we think the best method will be electro shock because it renders them unconscious really fast. We are trying to investigate that more, but I think many companies are trying to implement electrical stunning as a better method than chilling.