Well, here we are two weeks into the era of gravitational wave astronomy. I trust that by now you have read and heard all about the LIGO discovery of gravitational waves from two black holes merging and what it means for astronomy.
These are indeed exciting times and it is worth pausing to think about this announcement in the context of other big astronomical discoveries that were generations in the making. Perhaps the best historical analog for the gravitational wave search and detection is the search for the trigonometric parallax, or a method to measure the distance to stars. Its existence was long theorized, but observational evidence was harder to come by. Read More
Many of the questions I am asked regard how “true” science fiction concerning black holes might be, and whether worm holes, such as those featured in Stargate, are real or not. Invariably though, the one item that is almost assured to come up are the largely gruesome ways in which black holes might theoretically affect human beings and the Earth itself.
There are three properties of a black hole that are (in principle) measurable: their mass, their spin (or angular momentum) and their overall electronic charge. Indeed, these are the only three parameters that an outside observer can ever know about since all other information about anything that goes into making up a black hole is lost. This is known as the “no hair theorem”. Put simply: no matter how hairy or complex an object you throw into a black hole, it will get reduced down (or shaved) to its mass, charge and spin.
Of these parameters, mass is arguably the most significant. The very definition of a black hole is that it has its mass concentrated in to a vanishingly small volume – the “singularity”. And it is the mass of the black hole – and the huge gravitational forces that its mass generates – which does the “damage” to nearby objects.
One of the best known effects of a nearby black hole has the imaginative title of “Spaghettification”. In brief, if you stray too close to a black hole, then you will stretch out, just like spaghetti.
This effect is caused due to a gravitation gradient across your body. Imagine that you are headed feet first towards a black hole. Since your feet are physically closer to the black hole, they will feel a stronger gravitation pull toward it than your head will. Worse than that, your arms, by virtue of the fact that they’re not at the center of your body, will be attracted in a slightly different (vector) direction than your head is. This will cause parts of the body toward the edges to be brought inward. The net result is not only an elongation of the body overall, but also a thinning out (or compression) in the middle. Hence, your body or any other object, such as Earth, will start to resemble spaghetti long before it hits the center of the black hole.
The exact point at which these forces become too much to bear will depend critically on the mass of a black hole. For an “ordinary” black hole that has been produced by the collapse of a high mass star, this could be several hundred kilometers away from the event horizon – the point beyond which no information can escape a black hole. Yet for a supermassive black hole, such as the one thought to reside at the center of our galaxy, an object could readily sink below the event horizon before becoming spaghetti, at a distance of many tens of thousands of kilometers from its center. For a distant observer outside the event horizon of the black hole, it would appear that we progressively slow down and then fade away over time.
What would happen, hypothetically, if a black hole appeared out of nowhere next to Earth? The same gravitational effects that produced spaghettification would start to take effect here. The edge of the Earth closest to the black hole would feel a much stronger force than the far side. As such, the doom of the entire planet would be at hand. We would be pulled apart.
Equally, we might not even notice if a truly supermassive black hole swallowed us below its event horizon as everything would appear as it once was, at least for a small period of time. In this case, it could be some time before disaster struck. But don’t lose too much sleep, we’d have to be unfortunate to “hit” a black hole in the first place – and we might live on holographically after the crunch anyway.
Interestingly, black holes are not necessarily black. Quasars – objects at the hearts of distant galaxies powered by black holes – are supremely bright. They can readily outshine the rest of their host galaxy combined. Such radiation is generated when the black hole is feasting on new material. To be clear: this material is still outside the event horizon which is why we can still see it. Below the event horizon is where nothing, not even light, can escape. As all the matter piles up from the feast, it will glow. It is this glow that is seen when observers look at quasars.
But this is a problem for anything orbiting (or near) a black hole, as it is very hot indeed. Long before we would be spaghettified, the sheer power of this radiation would fry us.
For those who have watched Christopher Nolan’s film Interstellar, the prospect of a planet orbiting around a black hole might be an appealing one. For life to thrive, there needs to be a source of energy or a temperature difference. And a black hole can be that source. There’s a catch, though. The black hole needs to have stopped feasting on any material – or it will be emitting too much radiation to support life on any neighboring worlds.
What life would look like on such a world (assuming its not too close to get spaghettified, of course) is another matter. The amount of power received by the planet would probably be tiny compared to what Earth receives from the Sun. And the overall environment of such a planet could be equally bizarre. Indeed, in the creation of Interstellar, Kip Thorne was consulted to ensure the accuracy of the depiction of the black hole featured. These factors do not preclude life, it just makes it a tough prospect and very hard to predict what forms it could take.
One truism for me that I suspect holds some tiny bit of general truth for many across the broad, beautiful swath of humanity is that the longer I live the more history compresses.
Today the work Brahe, Kepler and Galileo did to understand the geometry of the solar system doesn’t seem as distant to me as the scenes from Happy Days did shortly after we landed on the moon. When I teach astronomy and physics I circle back to certain ideas repeatedly. One of these ideas is related to the evolving sense of the flow of time, wherever it may slip. This concept centers on my need to get students to come to terms with the notion that the ideas in their textbooks got there as a result of real struggles by real people. As clear and obvious as the textbook physics may appear, it almost assuredly was a dirty mess at the time. Read More
Don’t panic, future astronauts, but GMOs will probably accompany you on your adventures to deep space.
Scientists hope to genetically engineer organisms to survive off-Earth and to do some of the dirty work on spaceships and other planets. The field of study is called “space synthetic biology.” And this new frontier in genetic research could be key to opening up the final frontier.
Synthetic biology refers, generally speaking, to the work of giving some organism altered or even novel characteristics by changing its genes. Space synthetic biologists genetically alter organisms to make them more space-worthy — resistant to radiation or heat, for instance — and to make them useful to space missions — like turning Martian dirt into concrete. It sounds “out-there,” but microbes already make our planet habitable and pleasant.
“We’re breathing oxygen that was biologically produced,” says Lynn Rothschild, the head of the synthetic biology program at NASA’s Ames Research Center. “I’m wearing cotton that was biologically produced.”
We’re not going to take sheep on space missions, she clarifies, but we could take the capabilities of oxygen- and cotton-making plants and put them into the DNA of more portable life, like yeast. “Start looking at biology as technology,” she says, a “genetic hardware story” that could infuse all aspects of space missions.
Rothschild advises the Stanford-Brown team in the International Genetically Engineered Machine competition, where her groups have, among other things, made wires using DNA as a template; created a biodegradable drone; and taken genes from extreme bacteria and inserted them into E. coli to create hybrid organisms that resist extreme pH, temperature, and dryness. They called it the Hell Cell.
Such bio-based technology, according to a November report from a team led by Amor Menezes California Institute for Quantitative Biosciences in Berkeley, requires 26-85 percent less mass than “abiotic” (non-living) systems. For instance, a spaceship could carry a habitat to Mars, like the Apollo missions did to the moon, but no one wants to live in a tin can, and also that tin can is heavy.
“Think in analogy with early long-term travel on Earth,” says Rothschild, like pilgrims to North America. “They didn’t bring houses. They learned to live off the land.”
Future astronauts will have to live off of inhospitable land and also spaceships, which have no land. Menezes’s report sets forth a plan for those astronauts, suggesting directions the research could go. The microbes we use for terrestrial composting and waste treatment, for instance, produce nitrous oxide, which is spaceship go-juice. We could genetically engineer those microbes to do their duties in space, with different oxygen requirements and faster reaction capabilities but the same basic chemistry. Just by pooping and making trash, then, astronauts could create the raw material for fuel.
Once those refuse-creating colonists arrive on Mars, they could use carried-on microbes to mine the materials for building their new homes. Microbes that make acid could dissolve the Martian rock that surrounds metals, leaving just “the resource.” Or we could engineer microbes to dissolve the resource itself, so that it flows out and can then be reconstituted into a colonial outpost.
Construction companies on Mars could take the “regolith,” or surface material, and bind it together using natural glue, like mussel foot protein (engineered for optimal performance on Mars). Scientists could also make microbes that chew on the regolith and spit out calcium or iron to make “biocement.”
Poop processing, manufacturing, and construction all leave behind useful byproducts, like methane, which could help keep the colony’s lights on. The outpost, while electrified, wouldn’t have many frills. But scientists do have to ensure astronauts’ basics: air, water, and food, indefinitely.
Menezes recommends that we develop space-friendly microbes that can turn byproducts of wastewater treatment into food (yum!). While the food doesn’t have to be Michelin-star-quality, it does have to qualify as “nutrient-dense biomass that supplements astronaut dry-food while being versatile in flavor and texture.”
If the walls of a ship or colony were alive (it’s not creepy), the microbes could up-cycle carbon dioxide into oxygen and would — bonus! — shield astronauts from radiation. Not only does radiation zap our DNA with cancerous mutations, it also makes medicines expire faster.
People will still get sick in space, so synthetic biologists are also working on bio-based medical care. Microorganisms and plants could be engineered to make medicines and to shift the microbiome — the community that lives in symbiosis with each of us — back into order.
“If astronauts could grow their medicine in algae I think that would be super cool,” says Josiah Zayner, a space synthetic biologist at NASA’s Ames Research Center, who was not an author on the paper, “but I think it would take a lot of money and resources to make this happen.”
But what if the ship or colony were even more alive, Menezes wonders, full of biosensors and biological control systems? If it sounds a little too Battlestar Galactica-Cylon for comfort, don’t worry yet, says Zayner. “Honestly, I think this is just their ‘out there’ idea,” he says. “Systems that they are describing have not really been invented yet. They lost me at ‘hybrid robot version of tumor killing bacteria.’”
But it’s not that out there, contends Menezes.
“The space cybernetics grand challenge essentially calls for implementing control systems ideas into biological systems,” he says — the same control systems that put people on the moon and let Curiosity rove on Mars. But with biology. Integrating the two with technology will “take some time,” he continues, but “complete and tested space synthetic biology systems should be ready within a couple of decades, and if not in time for the first U.S. human Mars expedition, certainly by the second or third one.”
But even a cybernetic ship or colony with living walls, algae gardens, and nutrient-dense biomass isn’t quite enough for a self-sustaining, long-lived Martian habitat. To create that, we either need to make Mars a planet like Earth — or we need to make a miniature Earth on Mars.
To “terraform” a planet is to Earthify it. But “paraterraforming” is the more realistic step down: turning a smaller, contained space into a self-sustaining, human-friendly place. In the case of Mars, this would be a habitable spot surrounded by god-awful instant-death desert. Scientists would have to engineer an entire ecosystem that creates what astronauts need to eat, drink, breathe, and stay healthy, sane, and productive. All while recycling their waste products and keeping their environment cut off from the aforementioned god-awful instant-death desert — using microbes.
“This, I think should be the number-one research goal before missions to Mars,” says Zayner.
And the missions to Mars are what Menezes’ report looks toward.
“All of this is coming from the viewpoint of making it to Mars in the next 20 years and not from the viewpoint of what synthetic biology will be doing in 20 years,” says Zayner, “because that is extremely hard to plan for.” And it depends on the available of both cash and people to do the job.
Zayner also cautions that any life-based space systems will need to be tested and built years before they appear on a crewed capsule or a colony on the Red Planet. As a result, the bleeding-edge technology that exists when a Mars mission launches probably won’t be part of that Mars trip — well-characterized, older technology likely will be. That’s true in any space mission, which engineers blueprint and begin building many years before launch.
But Menezes says the gap between prototype and practical use is shrinking, largely because the space industry is no longer run entirely by a government.
“Just yesterday, I learned that there was a recent project that went from concept idea to actual space deployment within six months,” he says. “Although this timeline is atypical at the moment, with the advent of commercial space ventures, it is now possible to partner to quickly test and characterize fruitful ideas in space.”
But after the ship launches with its promising technology, problems could arise on Mars, too. The regolith that we might use for construction contains perchlorates, salts that can be toxic to humans. Toxic bricks do not an ideal colony build.
“Perchlorates are certainly a problem at the moment,” says Menezes. But we could figure out how to deal with those, and, in our initial attempts at exploiting Mars’s resources, use Mars’s air instead of its land. “For instance, 95 percent of the Mars atmosphere is carbon dioxide. This carbon dioxide will be the primary carbon source for the microbes.”
While making our own special-snowflake space biology sounds sci-fi, non-fictional scientists are working to make the concepts nonfictional, too. To engineer organisms that will be useful on other planets, they first look to our own world and its biology. And in altering and organizing those biological beasts into useful space systems, scientists will also learn how to make life better back on Earth.
“The possibilities of space synthetic biology are truly endless, yet each of them has immense importance back on Earth,” says Menezes.
Synthetic biological solutions to space problems in medicine, food, and carbon dioxide can address similar issues on Earth: personalized medicine, agriculture for growing populations, and fixing our carbon-dioxide-laden atmosphere. And while paraterraformed spaces give astronauts a safe place to sleep, the technologies can also help us learn to live sustainably on Earth. A Martian colony would be the ultimate zero-waste green space, whose ethos every earthling should get behind.
“I find the notion of doing ‘far-out space stuff’ that is simultaneously a priority on Earth really captivating and compelling,” says Menezes.
Louis Friedman has always balanced his optimistic vision for the future of human space exploration with a dose of reality, and his tempered outlook courses through his new book, Human Spaceflight From Mars to the Stars, in which he charts the distant future of human space travel.
Friedman is optimistic that human space exploration will continue well into the future. However, here’s that dose of reality from Friedman: humans will never venture beyond Mars, at least not in any historically significant way. Once humans tame Mars, how will humanity continue to explore cosmic frontiers, and to what end? Space travel, according to Friedman, will be an act more focused on transporting our minds — with the help of new technologies — rather than our bodies. Read More
Witnessing an aurora first-hand is a truly awe-inspiring experience. The natural beauty of the northern or southern lights captures the public imagination unlike any other aspect of space weather. But auroras aren’t unique to Earth and can be seen on several other planets in our solar system.
An aurora is the impressive end result of a series of events that starts at the sun. The sun constantly emits a stream of charged particles known as the solar wind into the depths of the solar system. When these particles reach a planet, such as Earth, they interact with the magnetic field surrounding it (the magnetosphere), compressing the field into a teardrop shape and transferring energy to it. Read More
The existence of parallel universes may seem like something cooked up by science fiction writers, with little relevance to modern theoretical physics. But the idea that we live in a “multiverse” made up of an infinite number of parallel universes has long been considered a scientific possibility – although it is still a matter of vigorous debate among physicists. The race is now on to find a way to test the theory, including searching the sky for signs of collisions with other universes.
It is important to keep in mind that the multiverse view is not actually a theory, it is rather a consequence of our current understanding of theoretical physics. This distinction is crucial. We have not waved our hands and said: “Let there be a multiverse.” Instead the idea that the universe is perhaps one of infinitely many is derived from current theories like quantum mechanics and string theory.
Imagine seeing the lights of cities spreading around the Nile Delta and then in less than an hour gazing down on Mount Everest. The astronauts on the International Space Station (ISS) are among the lucky few who will have this humbling, once-in-a-lifetime experience of seeing the beauty of Earth from space.
The ISS doesn’t just offer spectacular and countless views of the natural and man-made landscapes of our planet. It also immerses its residents into the Earth’s space environment and reveals how dynamic its atmosphere is, from its lower layers to its protective magnetic shield, constantly swept by the solar wind.
The best views are seen from the Cupola, an observation deck module attached to the ISS in 2010 and comprising seven windows. So, what are the amazing sights that you can see from the space station?
To understand the universe, you must know about atoms — about the forces that bind them, the contours of space and time, the birth and death of stars, the dance of galaxies, the secrets of black holes.
But that is not enough. These ideas cannot explain everything. They can explain the light of stars, but not the lights that shine from planet Earth. To understand these lights, you must know about life, about minds.
Somewhere in the cosmos, perhaps, intelligent life may be watching these lights of ours, aware of what they mean. Or do our lights wander a lifeless cosmos – unseen beacons, announcing that here, on one rock, the universe discovered its existence.
Either way, there is no bigger question. It’s time to commit to finding the answer – to search for life beyond Earth. The Breakthrough initiatives are making that commitment. We are alive. We are intelligent. We must know.
While self-aware humans have long wondered whether Earth is the only place like itself, we — and our technology — are finally advanced enough to answer that question. And with that power, astronomy’s quest du jour is to find habitable (and potentially inhabited) Earth-esque planets.
To discover biology from afar, scientists peer into planets’ atmospheres in search of evidence that something on their surfaces breathes and metabolizes. But planets are small (cosmically speaking) and far away, and their stars outshine them. Because of that latter problem, astrobiologists currently favor focusing on worlds orbiting small, dim red dwarf stars. Their meager light still nearly blinds us to their planets’ atmospheres, but visibility is better than it would be near a star like the sun.
But it’s not just the star that matters – it’s the other planets too. Astronomers have generally been looking for solar systems like ours, the only inhabited one we know of. That is to say, tidy solar systems where the planets have regular orbits in a flat disk.