Have you ever wondered why we age and grow old?
In the movie “The Curious Case of Benjamin Button,” Brad Pitt springs into being as an elderly man and ages in reverse.
To the bafflement of scientists, the fundamental laws of physics have no preference for a direction in time, and work just as well for events going forward or going backward in time. Yet, in the real world, coffee cools and cars break down. No matter how many times you look in the mirror, you’ll never see yourself grow younger. But if the laws of physics are symmetric with respect to time, then why do we experience reality with the arrow of time strictly directed from the past to the future?
A new paper just published in Annalen der Physik — which published Albert Einstein’s theories of special and general relativity — Dmitry Podolsky, a theoretical physicist now working on aging at Harvard University, and I explain how the arrow of time ‒ indeed time itself ‒ is directly related to the nature of the observer (that is, us).
Our paper shows that time doesn’t just exist “out there” ticking away from past to future, but rather is an emergent property that depends on the observer’s ability to preserve information about experienced events. Read More
A year ago today, a select group of scientists became the first people on the planet to learn that, after a century of theory and experiments, Albert Einstein was right all along.
Researchers at the Laser Interferometer Gravitational-Wave Observatory (LIGO) in Livingston, Louisiana had, at last, detected a gravitational wave. The ripple in space-time — a “chirp in the data — emanated from the merger of two black holes that collided some 1.3 billion years ago. This ripple in the fabric of the universe sent the science world abuzz when the findings were announced several months later in February. Read More
An exploding Falcon 9 could send ripples through space-timelines.
By now, you’ve probably heard about SpaceX’s Thursday morning “anomaly” at its Cape Canaveral launch pad. In fact, you can already watch video of it. Thankfully, no one was injured, but the AMOS-6 satellite payload, which would have brought Internet access to sub-Saharan Africa, was lost.
A pale red dot not far from our sun may be orbited by a pale blue dot much different than Earth.
In a shocking find, astronomers Wednesday announced their discovery of an Earth-sized planet orbiting the nearest star, Proxima Centauri, just 4.2 light-years away. This warm world, cataloged as Proxima b, sits smack in the middle of its habitable zone — the sweetest of sweet spots — where liquid surface water could exist.
But Proxima Centauri is not like our sun. It’s a cool, low-mass star known as a red dwarf. So the planet only qualifies as potentially habitable because it circles its sun in an orbit tighter than Mercury’s. Read More
The field equations of Einstein’s General Relativity theory say that faster-than-light (FTL) travel is possible, so a handful of researchers are working to see whether a Star Trek-style warp drive, or perhaps a kind of artificial wormhole, could be created through our technology.
But even if shown feasible tomorrow, it’s possible that designs for an FTL system could be as far ahead of a functional starship as Leonardo da Vinci’s 16th century drawings of flying machines were ahead of the Wright Flyer of 1903. But this need not be a showstopper against human interstellar flight in the next century or two. Short of FTL travel, there are technologies in the works that could enable human expeditions to planets orbiting some of the nearest stars. Read More
While astronaut Scott Kelly spent his year on the International Space Station, he expressed frustration with the ho-hum accommodations inside the ISS — it’s dullsville.
The temperature remains exactly the same day in and day out. The décor is a sterile mix of machines and wires. Astronauts are isolated, confined to small spaces and under a considerable amount of stress. While the vistas outside their window are no doubt spectacular, humans need a hint of nature’s greens and blues to stay happy.
The monotony of space can fray the nerves of even the most seasoned astronaut, and psychological stress is a serious side effect of living in a habitat of connected tubes orbiting Earth. So scientists at Dartmouth College are experimenting with virtual reality headsets like the Oculus Rift to see if simulated environments can break the monotony of space travel, and reduce psychological stress that astronauts experience on long duration missions.
“Things can go badly if the psychosocial elements aren’t managed properly. When you talk about longer and longer missions with a small crew it becomes really critical to have that social aspect right,” he says.
Jay Buckey — a former space shuttle astronaut — is now a professor of space medicine and physiology at Dartmouth. Each space shuttle mission runs around three weeks, so Buckey’s not experienced the same monotony as Scott Kelly. Despite his pleasant trip to space, he still felt called to help. Buckey and his colleagues are using calming imagery to see if virtual scenes reduce stress levels.
“I wanted to focus on many of the issues that would serve as a barrier to long duration spaceflight,” says Buckey. “The psychosocial adaptation element is crucial to a good mission.”
His theory is that exposure to bucolic landscapes — even virtual ones — can reduce stress. To do this, Buckey and his team created two types of “escapes” for the subjects to try. The test subjects were either given a trip to the lush green hills of Ireland, or a serene beach landscape in Australia. As a control, test subjects sat in a classroom and researchers measured their heart rate and skin conductance.
“We are assuming that natural scenes will be preferred,” explains Buckey. “But, people in an isolated and confined environment might want an urban scene.”
To quantify the stress relief, Buckey’s team will measure the electrodermal activity in the skin of their test subjects to track fluctuations of psychological arousal and stress, providing insights into who is responding best to a given scene.
Buckey is also adding another twist to his experiments: shining a heat lamp on subjects viewing a beach scene to enhance their virtual experience.
“VR is an immersive world and we would like to optimize the scenes to find out what it is about these that people find the most compelling. As the tech improves and you get higher definition video you can really immerse somebody in a nature scene,” says Buckey. “Would people rather have a vista, or animals, and what other kinds of sensations would people like?”
Currently astronauts on the International Space Station use a tool called the Virtual Space Station — essentially a virtual therapy session. This VR software doesn’t provide stress reduction in the way that Buckey is exploring, but it has tools for conflict resolution, and training on how to handle interpersonal disagreements if and when they arise.
Buckey’s experiments are still ongoing, so his results aren’t finalized. However, the notion that nature is good for our brain is nothing new — dozens of scientific studies back this up. In a more recent study, researchers from South Korea used fMRI to measure subjects’ brain activity when they looked at nature scenes versus urban scenes. Urban scenes activated the amygdala, which is linked to heightened anxiety and increased stress. On the other hand, nature scenes caused more blood to flow to regions in the brain associated with empathy and altruistic behavior.
At the University of Verona in Italy, researchers showed that “being in” a natural setting improved cognitive functioning, and participants completed tasks more efficiently with less mental fatigue. Nature can also lower our blood pressure and heighten our mood.
The data from the Dartmouth lab won’t be published for several more months, but the team hopes its experiment will move one step closer to helping future astronauts, and other people who work in isolation, cope with stress.
If it turns out that the data from Buckey’s experiments show a reduction in stress, future astronauts could perhaps work a regimen of VR medicine into their weekly routine. So far, Buckey thinks the preliminary results are encouraging, but “these are highly individualized responses, and is very subjective.”
“It depends on the outcome of what we have. We haven’t really proven that it works that well yet so I think its important for us to show that there’s a tangible benefit to having this.”
In 1980 a group of scientists ventured off into the cold and isolated region of Antarctica as part of the International Biomedical Expedition. The IBEA was designed to understand how the human body would acclimate to extremely cold environments, isolation and the psychological responses to this type of stress. It dramatically highlighted the need for stress reduction for team members.
As the expedition continued, crewmembers grew homesick, isolation wore them down and they grew more and more irritable. Several scientists on the team simply walked out of the experiment before it was completed, due to these stressors.
In the 1980s, psychological stress drove a rift between cosmonaut Valentin Lebedev and his commander Anatoly Berezovoy while they were living aboard the Russian Space Station Salyut 7.
Lebedev wrote a book called Diary of a Cosmonaut where he shared stories of conflicts so severe that they sometimes went weeks without speaking to each other. In space, and especially on a longer mission to Mars, communication is key. Conflicts of this scale aren’t an option. In other words, keeping stress levels low is key to planning a successful mission.
One of the most profound and exciting breakthroughs in planetary science in the last two decades has been the discovery of liquid methane lakes on the surface of Saturn’s largest moon Titan, and liquid oceans under the icy surfaces of many of the giant gas planets’ other moons. Thrillingly, these some of these “waters” may actually harbor life.
Unfortunately, we don’t know much about them. Probes such as Juno and Cassini can only get so close. Also, subsurface oceans can only be sensed indirectly. The European Space Agency’s Huygens probe did land on Titan in 2005, but on a solid surface rather than on liquid. So how can we explore these seas? Read More
I look at rocks on Mars for a living—a lot of rocks. Because of this, I’ve gotten pretty good at knowing what to expect and what not to expect when analyzing the chemical make-up of a Martian rock. You expect to find lots of basalt, the building block of all planets.
What I didn’t expect were large amounts of manganese. So when my colleagues and I found exactly that on a Martian rock called “Caribou” back in 2013, we thought, “This has to be a mistake.”
Trace amounts of the element manganese typically exist in basalt. To get a rock with as much manganese as Caribou has, the manganese needs to be concentrated somehow. The rock has to be dissolved in liquid water that also has oxygen dissolved in it.
If conditions are right, the manganese liberated from the rock can then precipitate as manganese oxide minerals. On Earth, dissolved oxygen in groundwater comes from our atmosphere. We’ve known for some time now that Mars once had vast oceans, lakes and streams. If we could peer onto Mars millions of years ago, we’d see a very wet world. Yet we didn’t think Mars ever had enough oxygen to concentrate manganese—and that’s why we thought the data from Caribou must have been an error.
So what do you do when you find a Martian rock with a chemistry you didn’t expect? You go look for more.
When NASA’s Curiosity rover arrived at the Kimberly region of Gale crater, we went to work, looking at the mineral-filled cracks in sandstones on the floor of what was once a deep lake. We used the ChemCam instrument, which sits atop Curiosity and was developed here at Los Alamos National Laboratory, to “zap” rocks on Mars and analyze their chemical make-up. (In less than four years since landing on Mars, ChemCam has analyzed roughly 1,500 rock and soil samples.)
When ChemCam fires its laser pulse, it vaporizes an area the size of a very small pinhead. The system’s telescope on the rover peers at the flash of glowing plasma created by the vaporized material and records the colors of light contained within it. This light allows us here on Earth to determine the elemental composition of the vaporized material.
And what did ChemCam discover? More rocks filled with manganese oxides. So Caribou was not a mistake — far from it.
We never expected to find manganese oxides on Martian rocks because we didn’t think Mars ever had the right environmental conditions to create them. We can look to Earth’s geological record for an explanation. More than 3 billion years ago, Earth had lots of water but no widespread deposits of manganese oxides until after photosynthesizing microbes raised the oxygen levels in our atmosphere.
Although there was already plenty of other microbial life on Earth at this time, these new photosynthetic microbes used sunlight energy in a new way and created a new type of waste product in the process: oxygen.
By adding oxygen to the atmosphere, these tiny microbes transformed Earth’s environment. Suddenly, minerals never before formed on Earth started being deposited, including manganese oxides. This monumental environmental shift is recorded in the chemistry of rocks of that age all over the world. Earth has never been the same since. (Some hypothesize that more complex life forms, such as humans, might never have developed without this atmospheric change.)
So to summarize: In the Earth’s geological record, the appearance of high concentrations of manganese marks a major shift in our atmosphere’s composition, from relatively low oxygen abundances to the oxygen-rich atmosphere we see today. The presence of the same types of materials on Mars suggests that something similar happened there. If that’s the case, what formed that oxygen-rich environment?
One way oxygen could have gotten into the Martian atmosphere is from the breakdown of water when Mars was losing its magnetic field.
Without a protective magnetic field to shield the surface from ionizing radiation, that radiation split water molecules into hydrogen and oxygen. Mars’ relatively low gravity couldn’t hold onto the very light hydrogen atoms, but the heavier oxygen atoms remained behind. Rocks absorbed much of this oxygen, leading to the rusty red dust that covers the surface today. While Mars’ famous red iron oxides require only a mildly oxidizing environment to form, manganese oxides require a strongly oxidizing environment. Finding manganese oxides suggests that past conditions were far more oxidizing than previously thought.
NASA’s Opportunity rover, which has been exploring Mars since 2004, also recently discovered high-manganese deposits in its landing site thousands of miles from Curiosity, which supports the idea that the conditions needed to form these materials were present well beyond Gale crater.
Of course, it’s hard to confirm whether the ionizing-radiation scenario I’ve presented here for creating Martian atmospheric oxygen actually occurred. But it’s important to note that this idea represents a departure in our understanding of how planetary atmospheres might become oxygenated. So far, abundant atmospheric oxygen has been treated as a so-called biosignature, or a sign of existing life.
The next step in this work is for scientists to better understand the relationship between manganese minerals and life. On Earth, they are highly related—but they certainly don’t need to be.
So how can we tell whether the manganese on Mars might actually be made by microbes? The answer is lots and lots of laboratory experiments. If it’s possible to distinguish between manganese oxides produced by life and those produced in a non-biological setting, we can apply that knowledge directly to Martian manganese observations to better understand their origin.
In the meantime, we’ll keep our eyes trained on the Martian surface and see what other secrets it has to reveal.
Nina Lanza is a staff scientist at Los Alamos National Laboratory, which has built and operated more than 500 spacecraft instruments for national defense. That background gives the Laboratory the expertise to develop discovery-driven instruments like ChemCam and its souped-up successor, SuperCam, also developed by the Laboratory and scheduled for the Mars 2020 rover mission.
Juno (JUpiter Near-polar Orbiter) is the sixth spacecraft to study Jupiter (give or take a few gravity assists), but will be the second to fall into orbit around the gas giant following the Galileo probe in 1995.
It is part of NASA’s New Frontiers space exploration program that specializes in researching the celestial bodies of the solar system. Juno was launched on August 5th, 2011 from Cape Canaveral Air Force Station in Florida and intended to be placed in a polar orbit around Jupiter to study the planet’s composition, magnetic and gravity fields, and the polar magnetosphere. Even though Juno’s scientific mission only lasts for a year, many more spacecraft are headed Jupiter’s way. Read More
Is there life beyond our planet? Astronomers have asked that question ever since we realized that there actually was something beyond our planet. Given the vastness of the universe, however, we’re not likely to journey out and meet it for ourselves anytime soon. Instead, astronomers are searching for a way to bridge the vast distances of interstellar space and search for subtle signs of life on other planets from right here on Earth.
SETI has garnered attention for its far-reaching aim: to make contact with intelligent extraterrestrial life. Other experiments, from the Golden Record tucked away in the Voyager missions, to the recently proposed Starshot program, hope that other civilizations will notice our wandering spacecraft.
If there is life, it will likely reveal itself through signs much more subtle than, say, a Dyson sphere. Instead, some astronomers are pinning their hopes on “biosignature” gases, molecules in a planet’s atmosphere that could only be produced by living organisms and observed from our corner of the universe. The telescopes of the near-future promise to give us the capability to peer into the atmospheres of distant planets and pick out their composition. But if life sends out gaseous greetings, what gases should we be “sniffing” for? Read More