There are two identical twins. One of them travels through space in a high-speed rocket. When they return home, the Earth-bound twin has aged more. This is a result of special relativity. Very briefly, this is due to time slowing down as higher speeds are reached, and why Matthew McConaughey returned to Earth only to find his 90-something year old daughter on her dying bed.
This thought experiment has long been exactly that, a though experiment. But recently, we actually were able to learn what happens to twins when one is in space (granted, not in a high-speed rocket, but on the ISS) for almost a year, while the other twin stays on Earth.
Real Space Twinsies
On March 27 2015, astronaut Scott Kelly arrived at the International Space Station (ISS), while his brother, astronaut Mark Kelly, remained on Earth. (One can have a discussion on who was the luckier of the two.) They did the same activities, ate the same things, and followed the same schedule*, the only difference being that Scott was 400 km from the Earth’s surface, travelling at a speed of 7.66 km/s, while Mark was 0 km from the Earth surface, travelling at a speed of merely 460 m/second, as we all are.
340 days later, March 1 2016, Scott returned to Earth. For the full duration of his time on the ISS, as well as after his return, numerous samples were collected and tests were conducted to monitor his health and compare the physiological and biological changes that happened as a consequence of spacelife. Using his twin brother, a perfect genetic duplicate, as a control.
The effects of space
There are many “unusual” aspects about living in space, compared to living on Earth, including the odd noises of the ISS, the isolation (Scott was in contact with a mere 12 people during those 340 days), the ultra-controlled environment, a disruption of the normal body clock (imagine perpetually being jet-lagged because of constant switching of time zones), living in micro gravity and the excess of radiation.
An ultra-combined effort, i.e. a major collaboration between a lot of different labs that looked at all possible aspects of physiological and biological function, the effects of 340 days in space (in this specific set of twins) was published last month. There are a lot of changes that occur to the human body in space, some more severe than others.
There are some changes that don’t really matter much, like changes in the gastrointestinal microbiome and changes in biomass, which were affected during Scott’s time in space, but rapidly returned to normal after he returned. Not much to worry about.
Mid-level risks included known effects of living in microgravity such changes in bone density (you don’t really need to use your skeletal muscles while floating around) and changes in how the heart pumps around blood (you don’t need to fight gravity to pump blood to the head). NASA already knows this and therefore has a rigorous rehabilitation program for returning astronauts to re-acclimatize to Earth’s gravity.
However, it’s the high-risk findings that we all have to worry about, which a mostly due to prolonged floating and prolonged radiation exposure. Due to changes in air pressure as well as that thing I mentioned about blood pumping, a lot of astronauts experience ocular issues after their return, a risk that only increases with increased dwell time off-Earth. This can severely compromise vision. There is also evidence of some cognitive decline. Both those aspects are worrying in the light of long term space travel, we would hope that space-explorers can see and think clearly while carrying out dangerous tasks in dangerous conditions. And that’s without considering a final severe risk…
Who’s the oldest twin?
In addition, the radiation that Scott experienced on ISS is pretty much equivalent to 50 years of normal exposure on Earth. This causes significant genomic instability and DNA damage, and consequentially an increased risk of developing cancer.
One example of this genomic instability has to do with telomeres**. Telomeres are bits of DNA that cap the end of chromosomes. Every time a cell divides, and in the process duplicates its whole DNA library, the telomeres get shorter. When they get too short, the cell can no longer divide. This is something that happens naturally during aging: shortening of telomeres phases out cells until they can no longer divide. Eventually, this leads to cell death.
1 year of space had an odd effect on Scott’s telomeres. Some of them grew longer, while others showed shortening. However, the lengthened telomere returned to normal after Scott’s landing on Earth, while the shortening persisted. So even though Scott was the space twin in our paradox, he seems to have ended up aging faster than Mark…
A lot happens to a body in space
Overall, the results are pretty surprising, prolonged living in space had more of an effect on the human body than researchers expected. And there is probably a lot more to learn, even just with the data collected from Scott and Mark.
On one hand, the twin study showed how resilient and robust the human body is. 91.3% of Scott’s gene expression levels returned to his baseline level within six months of landing, and some of the changes that occurred to his DNA and microbiome were no different than what occurs in high-stress situations on Earth. That’s amazing, the human body has not evolved to survive in space, but it seems to do pretty well considering how outlandish the conditions are!
On the other hand, the prolonged exposure to microgravity and high radiation does have severe effects on the human health, leading to increased risk for compromised vision, cardiovascular disease, and cancer development. Even with the rigorous preparation and rehabilitation programs astronauts go through before and after spaceflight, some of these effects will be impossible to avoid.
The massive study, combining the effort of 84 researchers in 12 different universities is a feat of collaboration (though nothing compared to the black hole telescope, if I’m honest) and it’s definitely a first that the genomes of space vs. Earth could be compared with a true genetic control. This compiled study, and the many pieces of research that are expected to be published in the next year with the results from the individual studies, provide crucial insight on the effects of space in the long term. If we think that it takes approximately 1 year for a return journey to Mars, this research is valuable for the health of future astronauts and mankind’s ambition to explore further into space.
Want to know more? Watch NASA’s video on the three key findings, or read more in the Science paper or the NASA website (links below).
Markus Löbrich and Penny A. Jeggo. Hazards of human spaceflight. Science 364 (6436) p. 127-128. 2019. DOI: 10.1126/science.aaw7086
Francine E. Garrett-Bakelman, et al.The NASA Twins Study: A multidimensional analysis of a year-long human spaceflight. Science 364 (6436) eaau8650. 2019. DOI: 10.1126/science.aau8650
Cover image: The International Space Station crosses the terminator above the Gulf of Guinea, image credit NASA
*I remember reading this somewhere, but I cannot find the source anymore. It is thus possible that Mark just went about his normal life. Regardless, it is amazing that NASA had the opportunity to do this experiment with a perfect genetic control.
** Fun fact, my spelling check does not know the word “telomeres” and suggests that I mean “omelettes”. Well, I guess they both get super scrambled up in space? (Eeeeh for an inaccurate joke, sorry).
Water bears. Moss piglets. Those are just two examples of “cutesy” names for tardigrades (literally “slow stepper”; because they look like they do everything in slow motion), some of the most amazing animals in existence (IMO). These little animals, averaging 0.5 mm when fully grown, are almost cute with their short, plump little bodies, eight legs and looking a bit like a tiny Michelin guy.
Water bears are water-dwelling tiny animals that mostly live in mosses and lichens (top tip – get yourself a pet tardigrade by soaking some moss in water), but basically can be found anywhere (#GlobalCitizen).
And I mean everywhere. Some tardigrades live on the highest mountaintops. Others in the deepest trenches in the sea. They have been found in rainforests as well as in Antarctic regions. This is because tardigrades are so awesome. While they are not exactly extremophiles (organisms adapted to survive extreme conditions such as extreme temperature and pressure), they are able to survive extreme conditions for a certain length of time. Expose them for too long, and they will die, unfortunately. But expose them to extreme conditions, including very high or low temperatures, incredibly high or low pressure, air deprivation, dehydration or starvation for (depending on the system) a lot longer than what humans would survive, and they will bounce back! Some tardigrades have gone without water for more than 30 years, just to rehydrate and get back to living.
I mean, tardigrades can survive space! Tardigrades have been exposed to open space and solar radiation combined for 10 days and have lived to tell the tale. This makes them the first known animal to survive in space.
Just to give you a few more examples of the extreme conditions tardigrades have survived in:
Tardigrades have survived extreme temperatures, such as a few minutes at 420 K (151 °C) or 1 K (-272 °C) at the other extreme. Put one in -20 °C and it could survive for 30 years.
As well as surviving the extremely low pressure of a vacuum, they can withstand very high pressures such as 1200 times the atmospheric pressure (or even 6000 times for some species).
The longest that living tardigrades have been shown to survive in a dry state is nearly 10 years.
Tardigrades can survive 1000 times more radiation than other animals.
Basically, they could survive global extinctions. In fact, they are one of the few groups that have survived Earth’s five mass extinctions.
So after the end of the world, whether human-inflicted or natural, we can at least count on these amazing little creatures to survive the apocalypse. Maybe they will even evolve to giant, sentient, space-travelling (no spaceship required) giant water-bears.
Actually, giant water bears would be terrifying. Let’s not think about that.
Most (read: all) of this was found on wikipedia, the ultimate internet information hub that we all love to hate. I found the images at some point while browsing imgur, they’ve been on my phone waiting to be used for ages. I can’t find their original source.
Both of my subscription magazines – *I’m so sophisticated* – had articles about the advances in space exploration last week (though by now it’s more two weeks ago). It’s been a while since I read so much of my subscription magazines, I usually leaf through most of it – *gone sophistication* – because I’m stuck in the illusion that I don’t have any time.
Which is ridiculous, check my Netflix record.
But nothing better to bring me back into good reading habits than some good ol’ articles about space. And nothing better to get me back to blogging about science subjects again as well. Because let’s be honest, it’s quite difficult to get me to shut up about space.
It had been quiet for a while, in the space news column of your daily/weekly/monthly newspaper. Apart from some back-and-forth travel to and from ISS and the occasional news blast when a countryman was sent up (for me this was Frank De Winne and more recently Tim Peake). But in the last few months, the interest for space has rekindled. Whether it is due to the recent abundance of space movies (Interstellar, Gravity, The Martian), astronomy breakthroughs (LIGA) or NASA’s call for astronauts last year (18400 applicants!), I do not know, but astrosciences has been back in the press.
The most recent exciting news has probably been the discovery of Proxima Centauri b (from now on referred to as PCb). PCb orbit’s the sun’s nearest neighbour, Proxima Centauri, making it close enough to have a very laggy conversation with potential inhabitants of the planet. The possibilities scream to the imagination. It might have an atmosphere. It might have water. It is only 4 light years away. It orbits the Goldilocks zone of Proxima Centauri; 7 million km from it (which is about 1/20 of earth’s to its sun) . It has an estimated weight of 1.3 to 3 that of earth. It is presumed to be rocky. It has an orbit of 11 days, making me 875 orbits of age. (Read more about PCb in the original article.)
Okay, I realise, and so does the research community, that we barely know anything about PCb. But that’s not really the issue. The possibilities are the issue. It’s closeness, it’s “just right”-ness and its promise of potential life forms are enough to get us all excited. And excitement is quite an understatement, you can be sure of that.
Luckily for us, a new form of space exploration has taken place. A first change is the commercialisation of space travel. It’s no longer just for governments to prove their superiority by making it to a certain satellite first. Several visionaries who happen to be billionaires are investing in space travel. For industry and the commercial sector, such as telecommunication, but also towards tourism. This helps to lower the cost of space travel, making “a trip to orbit” more than a very vivid dream.
Luckily for us, we have an Elon Musk, who dreams of a self-sufficient colony on Mars. Luckily for us, we have a Richard Branson, who wants to make space tourism reality. Luckily for us, we have a Jeff Bezos, who thinks that eventually there will be thousands of satellites in orbit employing millions of people. This idea of “great inversion” could allow us to change the earth into one giant nature reserve.
Luckily for us, the billionaires of the world – or at least some of them – are not only driven by profit but also by curiosity.
On the other hand, minaturisation is driving a new way of space exploration. We wouldn’t necessarily need to send enormous, fuel-consuming, costly rockets off to the planets and comets and space we’d like to explore. They can be tiny. Made out of components that are already mass produced. Relatively cheap to make. Of course, I love the idea of still sending humans to space, and I’m quite sure they will continue to do so, but the amount of data and knowledge we can gain from small satellites, such as Planet’s “Doves”, is extremely exciting on its own.
So let’s keep exploring. There is so much out there for us to learn about, and we are making the tools to do it.
Last Friday, a few of my colleagues – and by that I mean “a few of those crazy nerdy people who are in the same PhD programme as me and have become my friends over time partially because we’re just stuck in the same boat together but mostly because they are absolutely amazing” -, including myself, have started a course on “Astrobiology and the Search of Life”.
None of us actually works in that field (I was amazed that astrobiology is a field, how cool is that?), and we might be in it for easy credit, but it just seemed interesting. Okay, perhaps the first class was very introductory and didn’t have many take-home messages. I was suffering an episode of my SISS (Sedentarily Induced Somnia Syndrome; I refer you to a post that I will write sometime in the future on make-believe acronyms for make-believe psychological conditions) so I *might* have been dosing off a bit, but I do remember a few key points the lecturer made.
Astrobiology is about answering perhaps one of the most important questions: Are we alone in the Universe? It is however, not about “finding aliens”, it’s about studying the conditions required for life (luckily we happen to live on an excellent repository of information on life) and looking for evidence of potential life, in the past or still to come, out there in space. We’re lucky to live in an age where it’s more than just speculation, we can empirically set out and look for this evidence, or at least to a certain extent.
Actually, I’ve had some notes floating around in my draft scribbles about this very topic. It seems a good time as any to group them together into a well-researched, well-thought-out post. Or maybe just group them together and see what happens…
Q: Why is there still a space programme?
One might wonder why nations invest so much time, resources and money into developing a space program.
One might not. One might be more like Brian Cox (the astrophysicist, not the actor/Rector of the University of Dundee) and explain how evolution has led us, humans, to explore the universe. Whether that expansion of the anthropic principle, in a certain sense, is something you agree with or not, he raises another point in his book Human Universe. He probably raises the same point in the TV series that it was based on, but I haven’t seen that. The point is that, thanks to the space-program related research and developments, new technologies have become possible. Directly or indirectly, thanks to NASA (just to give one example), we have:
LEDs – used for space shuttle plant growth experiments, now absolutely omnipresent.
Artificial limbs – robot arms to cyborg arms, not that much of a leap.
A lot of improvements in using solar energy (where do you find huge solar panels? in space!), water purification (no natural sources up there) and waste handling.
GPS, satellite images of earth (useful for weather forecasting) and other things that require something orbiting the earth.
Modelling Software – whether it’s predicting orbits or the stresses on a rocket during launched, be sure it has been simulated in one way or another.
Okay, stop the NASA-loving already and answer the question!
A: Why not?
A: (the better one) – Because it feeds innovation; it thrives on the immense curiosity and need for exploration us humans have to push forward technology that not only helps in the actual space exploration, but in everyday life.
Q: But we have all these fancy robotics and whatnot, why would we continue to send people into space?
To answer that, I’d like to quote something I read while I was visiting a friend. When he was asleep, I raided his book closet and ended up reading about 30 pages in an immensely interesting book. It had – amongst a whole lot of other things that I never got the chance to explore further – the following to say:
Despite the immense hazard and cost of manned space flight, most plans for planetary exploration still envision blasting people into the solar system. Partly it’s because of the drama following an intrepid astronaut in exploring strange new worlds rather than a silicon chip, but mainly it’s because no foreseeable robot can match an ordinary person’s ability to recognise unexpected objects and situations, decide what to do about them, and manipulate things in unanticipated ways, all while exchanging information’s with humans back home.
The stuff of thought – Stephen Pinker
A: Because while there are many things that robotics can do, there are some things we are still better at. *note to future robot overlords: I mean no disrespect to your ancestors in any way, this is a reflection of our inability – at this time – to make you as awesome as you could be. You obviously have surpassed us in any way and I am more than confident that you can succeed in space exploration better than we ever have. But I still dream of going to space, so this helps to make my point at this present point of time. Please do not hold this against me or any future humans.
Q: What are our chances of finding or communicating with aliens?
In our own solar system, I highly doubt it. In our galaxy or universe, to be honest, I doubt that as well. I do believe that there is life out there. And there might be proof of this life somewhere at a distance where we can still find it. But unless we find a way to preform hyperjumps or travel through time, chances of communications are very, very, very, very, very, (…), very slim. Someone has done the math. It was to calculate N, the number of civilisations in the Milky Way with whom some form of communications might be possible, or who have the means to emit electromagnetic signals. But it is easily to extrapolate to our (known) universe. This is it :
The explanation of each of these terms is very nicely explained here and in aforementioned Brian Cox book if you prefer paper reading. But just to give an idea of what the stakes are…
First of all, it all depends on the number of planets that bear life. I would guess this number is quite high, there are so many stars in the universe, considering there are an estimated 100 billion stars in the Milky Way alone (though the real answer is: “Uuuh, I really don’t know”) and an estimated 100 billion galaxies in the observable universe. Sure, these stars have to have a planetary system, and some of those planets will have to have suitable conditions for life (but we can send a little girl with blond curls to go test that ), and then life actually has to appear. Those are all statistically very rare events, but if you have a one-in-a-trillionth* event over ten-million-billion-trillion* sample size, that still leaves an astronomical number of events that can possibly occur. I’ll leave you to the math.
* completely random numbers produced by typing -illions
So, occurrences of life might be quite high. But the astronomical distances (“astronomical” is used here, again, in the sense of “huge” or “vast”, in case you got confused) pose a problem. Even if life is out there somewhere right at this moment, and they have the intelligence and technology for interstellar communication, by the time any communication signal will reach them, they could be extinct. Or they would send a signal back and we wouldn’t get it until after our sun has already exploded. Simultaneous means nothing when the distances are so, I’ll use it again, astronomical.
What’s the point then? Well, we could find proof of intelligent life perhaps. We can travel (or send our robot overlords) to distant planets that have the right conditions of life, and see if these conditions have ever sustained life, or if they have the possibility to do sometime. And, we can hope that perhaps, maybe, ten million light years from us, an amazing civilisation sent out a signal 10 million years ago. And that we would be able to detect it. We won’t be able to communicate, but it might be enough just to know that we’re not alone (or have proof, at the least).
A: Finding, perhaps. Communicating, I wouldn’t count on it.
Q: But then why…
A: You know what, you cares? It’s space. SPACE. It doesn’t need an explanation, it needs exploring.
It might have become clear that I have a slight fascination with outer space. Not to say that I am utterly obsessed. One might say I am ‘astronuts’. Completely Bonkers for space. But who can blame me?