NASA’s Opportunity explores Spirit Mound after descending down Marathon Valley and looks out across the floor of vast Endeavour crater. This navcam camera photo mosaic was assembled from raw images taken on Sol 4505 (25 Sept 2016) and colorized. Credit: NASA/JPL/Cornell/ Ken Kremer/kenkremer.com/Marco Di Lorenzo
NASA’s Opportunity explores Spirit Mound after descending down Marathon Valley and looks out across the floor of vast Endeavour crater. This navcam camera photo mosaic was assembled from raw images taken on Sol 4505 (25 Sept 2016) and colorized. Credit: NASA/JPL/Cornell/ Ken Kremer/kenkremer.com/Marco Di Lorenzo
And as we are fond of reporting – the best is yet to come. After experiencing 4500 Martian sunsets, Opportunity has been granted another mission extension and she is being targeted to drive to an ancient gully where life giving liquid water almost certainly once flowed on our solar systems most Earth-like planet.
See Opportunity’s current location around ‘Spirit Mound” – illustrated in our new photo mosaic panoramas above and below.
NASA’s Opportunity rover scans ahead to Spirit Mound and vast Endeavour crater as she celebrates 4500 sols on the Red Planet after descending down Marathon Valley. This navcam camera photo mosaic was assembled from raw images taken on Sol 4500 (20 Sept 2016) and colorized. Credit: NASA/JPL/Cornell/ Ken Kremer/kenkremer.com/Marco Di Lorenzo
Opportunity was launched on a Delta II rocket from Cape Canaveral Air Force Station in Florida on July 7, 2003.
“We have now exceeded the prime-mission duration by a factor of 50,” noted Opportunity Project Manager John Callas of NASA’s Jet Propulsion Laboratory, Pasadena, California.
“Milestones like this are reminders of the historic achievements made possible by the dedicated people entrusted to build and operate this national asset for exploring Mars.”
The newest 2 year extended mission phase just began on Oct. 1 as the rover was stationed at the western rim of Endeavour crater at the bottom of Marathon Valley at a spot called “Bitterroot Valley.”
And at this moment, as Opportunity reached and surpassed the 4500 Sol milestone, she is investing an majestic spot dubbed “Spirit Mound” – and named after her twin sister “Spirit” – who landed 3 weeks earlier!
This scene from the panoramic camera (Pancam) on NASA’s Mars Exploration Rover Opportunity shows “Spirit Mound” overlooking the floor of Endeavour Crater. The mound stands near the eastern end of “Bitterroot Valley” on the western rim of the crater, and this view faces eastward. The component images for this mosaic were taken on Sept. 21, 2016, during the 4,501st Martian day, or sol, of Opportunity’s work on Mars. Credit: NASA/JPL-Caltech/Cornell/Arizona State Univ.
Endeavour crater spans some 22 kilometers (14 miles) in diameter. Opportunity has been exploring Endeavour since arriving at the humongous crater in 2011.
Endeavour crater was formed when it was carved out of the Red Planet by a huge meteor impact billions of years ago.
But now for the first time she will explore the craters interior, after spending 5 years investigating the exterior and climbing to a summit on the rim and spending several year exploring the top before finally descending down the Marathon Valley feature to investigate clay minerals formed in water.
“The longest-active rover on Mars also will, for the first time, visit the interior of the crater it has worked beside for the last five years,” said NASA officials.
Marathon Valley measures about 300 yards or meters long. It cuts downhill through the west rim of Endeavour crater from west to east – the same direction in which Opportunity drove downhill from a mountain summit area atop the crater rim. See our route map below showing the context of the rovers over dozen year long traverse spanning more than the 26 mile distance of a Marathon runners race.
Opportunity is now being targeted to explore a gully carved out by water.
“We are confident this is a fluid-carved gully, and that water was involved,” said Opportunity Principal Investigator Steve Squyres of Cornell University, Ithaca, New York.
“Fluid-carved gullies on Mars have been seen from orbit since the 1970s, but none had been examined up close on the surface before. One of the three main objectives of our new mission extension is to investigate this gully. We hope to learn whether the fluid was a debris flow, with lots of rubble lubricated by water, or a flow with mostly water and less other material.”
Furthermore, in what’s a very exciting announcement the team “intends to drive Opportunity down the full length of the gully, onto the crater floor” – if the rover continues to function well during the two year extended mission which will have to include enduring her 8th frigid Martian winter in 2017.
And as is always the case, scientists will compare these interior crater rocks to those on the exterior for clues into the evolution, environmental and climatic history of Mars over billions of years.
“We may find that the sulfate-rich rocks we’ve seen outside the crater are not the same inside,” Squyres said. “We believe these sulfate-rich rocks formed from a water-related process, and water flows downhill. The watery environment deep inside the crater may have been different from outside on the plain — maybe different timing, maybe different chemistry.”
NASA’s Opportunity rover discovers a beautiful Martian dust devil moving across the floor of Endeavour crater as wheel tracks show robots path today exploring the steepest ever slopes of the 13 year long mission, in search of water altered minerals at Knudsen Ridge inside Marathon Valley on 1 April 2016. This navcam camera photo mosaic was assembled from raw images taken on Sol 4332 (1 April 2016) and colorized. Credit: NASA/JPL/Cornell/ Ken Kremer/kenkremer.com/Marco Di Lorenzo
As of today, Sol 4522, Oct 12, 2016, Opportunity has taken over 214,400 images and traversed over 26.99 miles (43.44 kilometers) – more than a marathon.
The power output from solar array energy production is currently 472 watt-hours, before heading into another southern hemisphere Martian winter in 2017.
Meanwhile Opportunity’s younger sister rover Curiosity traverses and drills into the basal layers at the base of Mount Sharp.
Stay tuned here for Ken’s continuing Earth and planetary science and human spaceflight news.
12 Year Traverse Map for NASA’s Opportunity rover from 2004 to 2016. This map shows the entire path the rover has driven on the Red Planet during more than 12 years and more than a marathon runners distance for over 4515 Sols, or Martian days, since landing inside Eagle Crater on Jan 24, 2004 – to current location at the western rim of Endeavour Crater after descending down Marathon Valley. Rover surpassed Marathon distance on Sol 3968 and marked 11th Martian anniversary on Sol 3911. Opportunity discovered clay minerals at Esperance – indicative of a habitable zone – and searched for more at Marathon Valley and is now at Spirit Mound on the way to a Martian gully. Credit: NASA/JPL/Cornell/ASU/Marco Di Lorenzo/Ken Kremer/kenkremer.com
NASA will make a “surprising” announcement about Jupiter’s moon Europa on Monday, Sept. 26th, at 2:00 PM EDT. They haven’t said much, other than there is “surprising evidence of activity that may be related to the presence of a subsurface ocean on Europa.” Europa is a prime target for the search for life because of its subsurface ocean.
The new evidence is from a “unique Europa observing campaign” aimed at the icy moon. The Hubble Space Telescope captured the images in these new findings, so maybe we’ll be treated to some more of the beautiful images that we’re accustomed to seeing from the Hubble.
Images from NASA’s Galileo spacecraft show the intricate detail of Europa’s icy surface. Image: NASA/JPL-Caltech/ SETI Institute
We always welcome beautiful images, of course. But the real interest in Europa lies in its suitability for harboring life. Europa has a frozen surface, but underneath that ice there is probably an ocean. The frozen surface is thought to be about 10 – 30 km thick, and the ocean may be about 100 km (62 miles) thick. That’s a lot of water, perhaps double what Earth has, and that water is probably salty.
Back in 2012, the Hubble captured evidence of plumes of water vapor escaping from Europa’s south pole. Hubble didn’t directly image the water vapor, but it “spectroscopically detected auroral emissions from oxygen and hydrogen” according to a NASA news release at the time.
This artist’s illustration shows what plumes of water vapour might look like being ejected from Europa’s south pole. Image: NASA, ESA, L. Roth (Southwest Research Institute, USA/University of Cologne, Germany) and M. Kornmesser.
There are other lines of evidence that support the existence of a sub-surface ocean on Europa. But there are a lot of questions. Will the frozen top layer be several tens of kilometres thick, or only a few hundred meters thick? Will the sub-surface ocean be warm, liquid water? Or will it be frozen too, but warmer than the surface ice and still convective?
Two models of the interior of Europa. Image: NASA/JPL.
Hopefully, new evidence from the Hubble will answer these questions definitively. Stay tuned to Monday’s teleconference to find out what NASA has to tell us.
These are the scientists who will be involved in the teleconference:
Paul Hertz, director of the Astrophysics Division at NASA Headquarters in Washington
William Sparks, astronomer with the Space Telescope Science Institute in Baltimore
Britney Schmidt, assistant professor at the School of Earth and Atmospheric Sciences at Georgia Institute of Technology in Atlanta
Jennifer Wiseman, senior Hubble project scientist at NASA’s Goddard Space Flight Center in Greenbelt, Maryland
The NASA website will stream audio from the teleconference.
An artist's concept of the Europa mission. The multi-year mission would conduct fly-bys of Europa designed to protect it from the extreme environment there. Image: NASA/JPL-Caltech
Jupiter’s moon Europa is a juicy target for exploration. Beneath its surface of ice there’s a warm salty, ocean. Or potentially, at least. And if Earth is our guide, wherever you find a warm, salty, ocean, you find life. But finding it requires a dedicated, and unique, mission.
If each of the bodies in our Solar System weren’t so different from each other, we could just have one or two types of missions. Things would be much easier, but also much more boring. But Europa isn’t boring, and it won’t be easy to explore. Exploring it will require a complex, custom mission. That means expensive.
NASA’s proposed mission to Europa is called the Europa Clipper. It’s been in the works for a few years now. But as the mission takes shape, and as the science gets worked out, a parallel process of budget wrangling is also ongoing. And as reported by SpaceNews.com there could be bad news incoming for the first-ever mission to Europa.
Images from NASA’s Galileo spacecraft show the intricate detail of Europa’s icy surface. Image: NASA/JPL-Caltech/ SETI Institute
At issue is next year’s funding for the Europa Clipper. Officials with NASA’s Outer Planets Assessment Group are looking for ways to economize and cut costs for Fiscal Year (FY) 2017, while still staying on track for a mission launch in 2022.
According to Bob Pappalardo, Europa Clipper’s project scientist at the Jet Propulsion Laboratory, funding will be squeezed in 2017. “There is this squeeze in FY17 that we have,” said Pappalardo. “We’re asking the instrument teams and various other aspects of the project, given that squeeze, what will it take in the out years to maintain that ’22 launch.”
As for the actual dollar amounts, there are different numbers floating around, and they don’t all jive with each other. In 2016, the Europa Mission received $175 million from Congress, but in the administration’s budget proposal for 2017, they only requested $49.6 million.
There’s clearly some uncertainty in these numbers, and that uncertainty is reflected in Congress, too. An FY 2017 House bill earmarks $260 million for the Europa mission. And the Senate has crafted a bill in support of the mission, but doesn’t allocate any funding for it. Neither the Senate nor the Congress has passed their bills.
This is not the first time that a mis-alignment has appeared between NASA and the different levels of government when it comes to funding. It’s pretty common. It’s also pretty common for the higher level of funding to prevail. But it’s odd that NASA’s requested amount is so low. NASA’s own low figure of $49.6 million is fuelling the perception that they themselves are losing interest in the Europa Clipper.
But SpaceNews.com is reporting that that is not the case. According to Curt Niebur, NASA’s program scientist for the Europa mission, “Everyone is aware of how supportive and generous Congress has been of this mission, and I’m happy to say that that support and encouragement is now shared by the administration, and by NASA as well. Everybody is on board the Europa Clipper and getting this mission to the launch pad as soon as our technical challenges and our budget will allow.”
What all this seems to mean is that the initial science and instrumentation for the mission will be maintained, but no additional capacity will be added. NASA is no longer considering things like free-flying probes to measure the plumes of water ice coming off the moon. According to Niebur, “The additional science value provided by these additions was not commensurate with the associated impact to resources, to accommodation, to cost. There just wasn’t enough science there to balance that out.”
The Europa Clipper will be a direct shot to Europa, without any gravity assist on the way. It will likely be powered by the Space Launch System. The main goal of the mission is to learn more about the icy moon’s potential habitability. There are tantalizing clues that it has an ocean about 100 km thick, kept warm by the gravity-tidal interactions with Jupiter, and possibly by radioactive decay in the rocky mantle. There’s also some evidence that the composition of the sub-surface ocean is similar to Earth’s.
Mars is a fascinating target, no doubt about it. But as far as harbouring life, Europa might be a better bet. Europa’s warm, salty ocean versus Mar’s dry, cold surface? A lot of resources have been spent studying Mars, and the Europa mission represents a shift in resources in that regard.
It’s unfortunate that a few tens of million dollars here or there can hamper our search for life beyond Earth. But the USA is a democracy, so that’s the way it is. These discrepancies and possible disputes between NASA and the different levels of government may seem disconcerting, but that’s the way these things get done.
This scene shows NASA's Curiosity Mars rover at a location called "Windjana," where the rover found rocks containing manganese-oxide minerals, which require abundant water and strongly oxidizing conditions to form. Credits: NASA/JPL-Caltech/MSSS
This scene shows NASA’s Curiosity Mars rover at a location called “Windjana,” where the rover found rocks containing manganese-oxide minerals, which require abundant water and strongly oxidizing conditions to form. Credits: NASA/JPL-Caltech/MSSS
New chemical science findings from NASA’s Mars rover Curiosity indicate that ancient Mars likely had a higher abundance of molecular oxygen in its atmosphere compared to the present day and was thus more hospitable to life forms, if they ever existed.
Thus the Red Planet was much more Earth-like and potentially habitable billions of years ago compared to the cold, barren place we see today.
Manganese-oxide minerals require abundant water and strongly oxidizing conditions to form.
“Researchers found high levels of manganese oxides by using a laser-firing instrument on the rover. This hint of more oxygen in Mars’ early atmosphere adds to other Curiosity findings — such as evidence about ancient lakes — revealing how Earth-like our neighboring planet once was,” NASA reported.
The newly announced results stem from results obtained from the rovers mast mounted ChemCam or Chemistry and Camera laser firing instrument. ChemCam operates by firing laser pulses and then observes the spectrum of resulting flashes of plasma to assess targets’ chemical makeup.
“The only ways on Earth that we know how to make these manganese materials involve atmospheric oxygen or microbes,” said Nina Lanza, a planetary scientist at Los Alamos National Laboratory in New Mexico, in a statement.
“Now we’re seeing manganese oxides on Mars, and we’re wondering how the heck these could have formed?”
The discovery is being published in a new paper in the American Geophysical Union’s Geophysical Research Letters. Lanza is the lead author.
The manganese oxides were found by ChemCam in mineral veins investigated at “Windjana” and are part of geologic timeline being assembled from Curiosity’s research expedition across of the floor of the Gale Crater landing site.
Scientists have been able to link the new finding of a higher oxygen level to a time when groundwater was present inside Gale Crater.
“These high manganese materials can’t form without lots of liquid water and strongly oxidizing conditions,” says Lanza.
“Here on Earth, we had lots of water but no widespread deposits of manganese oxides until after the oxygen levels in our atmosphere rose.”
The high-manganese materials were found in mineral-filled cracks in sandstones in the “Kimberley” region of the crater.
Curiosity’s Panoramic view of Mount Remarkable at ‘The Kimberley Waypoint’ where rover conducted 3rd drilling campaign inside Gale Crater on Mars. The navcam raw images were taken on Sol 603, April 17, 2014, stitched and colorized. Credit: NASA/JPL-Caltech/Ken Kremer – kenkremer.com/Marco Di Lorenzo. Featured on APOD – Astronomy Picture of the Day on May 7, 2014
High concentrations of manganese oxide minerals in Earth’s ancient past correspond to a major shift in our atmosphere’s composition from low to high oxygen atmospheric concentrations. Thus its reasonable to suggest the same thing happened on ancient Mars.
As part of the investigation, Curiosity also conducted a drill campaign at Windjana, her 3rd of the mission.
Composite photo mosaic shows deployment of NASA Curiosity rovers robotic arm and two holes after drilling into ‘Windjana’ sandstone rock on May 5, 2014, Sol 621, at Mount Remarkable as missions third drill target for sample analysis by rover’s chemistry labs. The navcam raw images were stitched together from several Martian days up to Sol 621, May 5, 2014 and colorized. Credit: NASA/JPL-Caltech/Ken Kremer – kenkremer.com/Marco Di Lorenzo
How much manganese oxide was detected and what is the meaning?
“The Curiosity rover observed high-Mn abundances (>25 wt% MnO) in fracture-filling materials that crosscut sandstones in the Kimberley region of Gale crater, Mars,” according to the AGU paper.
“On Earth, environments that concentrate Mn and deposit Mn minerals require water and highly oxidizing conditions, hence these findings suggest that similar processes occurred on Mars.”
“Based on the strong association between Mn-oxide deposition and evolving atmospheric dioxygen levels on Earth, the presence of these Mn-phases on Mars suggests that there was more abundant molecular oxygen within the atmosphere and some groundwaters of ancient Mars than in the present day.”
Stay tuned here for Ken’s continuing Earth and planetary science and human spaceflight news.
The peahen (at left) and the peacock (at right). The peacock’s elaborate plumage and many other similar animal ornaments posed a troubling difficulty for Charles Darwin in his development of the theory of evolution, since they seemed to have no value for survival. The peacocks that were everywhere present in English gardens were a frustrating and ever-present reminder of the difficulty. “The sight of a feather in a peacock’s tail”, Darwin wrote, “whenever I gaze at it, makes me sick!”. Darwin solved the problem with his theory of sexual selection, which posits that such ornaments evolved because they help animals to woo mates, and thereby pass the trait into the next generation. Since mating in peafowl is by female choice, elaborate tail feathers are vital to the peacock, but unnecessary to the peahen. Sexual selection is increasingly recognized as a central evolutionary process by modern biologists. Evolutionary psychologist Dr. Geoffrey Miller posits that the enormous human brain evolved by sexual selection through the choices of both genders. Understanding how human intelligence evolved here on Earth is critical to understanding whether or not alien civilizations are likely to exist. Picture is from the Miho Museum, Shiga, Japan, 1781, public domain.
In the first instalment of this series, we saw that intelligence, of various sorts, is widespread across the animal kingdom. Workshop presenter Anna Dornhaus, who studies collective decision-making in insects as an associate professor at the University of Arizona, showed that even insects, with their diminutive brains, exhibit a surprising cognitive sophistication. Intelligence, of various sorts, is a likely and probable evolutionary product.
Animals evolve the cognitive abilities that they need to meet the demands of their own particular environments and lifestyles. Sophisticated brains and cognition have evolved many times on Earth, in many separate evolutionary lineages. But, of the millions of evolutionary lineages that have arisen on Earth in the 600 million years since complex life appeared, only one, that which led to human beings, produced the peculiar combination of cognitive traits that led to a technological civilization. What this tells us is that technological civilization is not the inevitable product of a long term evolutionary trend, it is rather the quirky and contingent product of particular circumstances. But what might those circumstances have been, and just how special and improbable were they?
Dr. Geoffery Miller is an associate professor of psychology at the University of New Mexico, and is the author of a 2001 book, The Mating Mind, where he explains his theory that human intelligence evolved by sexual selection to a general audience. He presented at the METI Institute conference in Puerto Rico, in May 2016. Picture used with permission.
Workshop presenter Geoffrey Miller is an associate professor of psychology at the University of New Mexico. Miller thinks he has an answer to the question of what the special circumstances that produced human evolution were. Our protohuman ancestors inhabited the African savanna. But so do many other mammals that don’t need enormous brains to survive there. The evolutionary forces driving the production of our large brains, Miller surmises, can’t be due to the challenges of survival. He thinks instead that human evolution was guided by an intelligence. But Miller is no creationist, nor does he have the alien monolith from the 1960’s science fiction classic 2001: A Space Odyssey in mind. Miller’s guiding intelligence is the intelligence that our ancestors themselves used when they selected their mates.
Miller’s theory harkens back to the ideas of the founder of modern evolutionary theory, the nineteenth century British naturalist Charles Darwin. Darwin proposed that evolution works through a process of natural selection. Animal offspring vary one from another, and are produced in too great of numbers for all of them to survive. Some starve, some are eaten by predators, others fall prey to the numerous other hazards of the natural world. A few survive to produce offspring, thereby passing on the traits that allowed them to survive. Down the generations, traits that aided survival become more elaborate and useful and traits that did not, vanished. Charles Darwin published his theory of evolution, in his book, The Origin of Species, in 1859. The theory was inspired, in part, by observations he made during his five year voyage as a naturalist on board the HMS Beagle and has become the central principle of much of modern biology. Picture by George Richmond (1830’s) public domain.
But Darwin was troubled by a serious problem with his theory. He knew that many animals have prominent traits that don’t seem to contribute to their survival, and are even counterproductive to it. The bright colors of many insects, the colors, elaborate plumage, and songs of birds, the huge antlers of elk, were all prominent and costly traits that couldn’t be explained by his theory of natural selection. Peacocks, with their elaborate tail feathers were everywhere in English gardens, and came to torment him.
At last, Darwin found the solution. To produce offspring, an animal must do more than just survive, it must find a partner to mate with. All the traits which worried Darwin could be explained if they served to make their bearers sexier and more beautiful to prospective mates than other competing members of their own gender. If peahens like elaborate plumage, then in each generation, they will choose to mate with the males with the most elaborate tail feathers, and reject the rest. Through the competition for mates, peacock tails will become more and more elaborate down the generations. Darwin called his new theory sexual selection.
Many subsequent evolutionary biologists regarded sexual selection as of limited importance, and lumped it in with natural selection, which was said to favor traits conducive to survival and reproductive success. However, in recent decades evolutionary biologists have come to view sexual selection in a much more favorable light. Geoffrey Miller proposed that the human brain evolved through sexual selection. Human beings, he supposes, are sapiosexual; that is, they are sexually attracted by intelligence and its products. The preference for selecting intelligent mates produced greater intelligence, which in turn allowed our ancestors to become more discerning in selecting more intelligent mates, producing a kind of amplifying feedback loop, and an explosion of intelligence.
On this account, language, music, dancing, humor, art, literature, and perhaps even morality and ethics exist because those who were good at them were deemed sexier, or more trustworthy and reliable, and were thus more successful in securing mates than those who weren’t. The elaborate human brain is like the elaborate peacock’s tail. It exists for wooing mates and not for survival. There are some important ways in which protohumans were different from peafowl. Both males and females are choosy and both have large brains. Protohumans, unlike peafowl, probably formed monogamous pair bonds. Miller’s theory has complexities that space won’t permit us to explore here. To show that his theory can work, Miller needed to develop a computer model.
The evolution of protohuman intelligence through geography and time. Homo egaster lived in the early Pleistocene between 1.9 and 1.4 million years ago and had a brain about half the size of modern Homo sapiens. It developed advanced stone tools, and may have domesticated fire. It was closely related to Homo erectus. Homo antecessor lived from 1.2 million to 800,000 years ago and spread from Africa into Europe. It’s brain was also about half as large as that of ours. Homo rhodesiensis lived about 120,000 to 300,000 years ago. Our species, Homo sapiens, arose in Africa about 200,000 years ago and spread throughout much of the world. Homo neanderthalensis had a brain capacity somewhat larger than that of modern humans, and its larger eye sockets suggest keener vision. They disappeared about 30,000 years ago, and may have died out, in part, through competition with Homo sapiens and cooling of the climate. Public Library of Science 2003.
If Miller is right, then just how probable is the evolution of a technological civilization, and how likely is it that we will find them elsewhere in the galaxy? Miller thinks that if complex life exists on other planets or moons, it is likely to evolve reproduction through sex, just as has happened here on Earth. For complex organisms that depend on a large and complicated body of genetic information, most mutations will be neutral or harmful. In sexual reproduction half the genes of one’s offspring come from each parent. Without this mixing of genes from other individuals, asexual lineages are likely to falter and go extinct due to an accumulation of harmful mutations. Unless sexually reproducing creatures choose their mates purely at random, sexual selection is an inevitability. So, the basic conditions for runaway sexual selection to produce a brain suited to language and technology probably exists on other worlds with complex life.
One problem, though, that Anna Dornhaus pointed out, is that in sexual selection, the trait that gets exaggerated is essentially arbitrary. There are many bird species with elaborate plumage, but none exactly like the peacock. There are many species where brains and cognitive traits matter for mating success, like the singing ability of nightingales and many other birds, or gibbons, or whales. Male bower birds build complicated structures, called bowers, out of found items, like sticks and leaves and stones and shells, to attract a female. Chimpanzees engage in complex power struggles that involve negotiation, grooming, and fighting their way to the top.
But despite the selective success of cognition and braininess in many species, our specific human sort of intelligence, with language and technology, has happened only once on Earth, and therefore might be rare in the universe. If our ancestors had found big noses rather than big brains sexy, then we might now have enormous noses rather than enormous radio telescopes capable of signaling to other worlds.
Miller is more optimistic. “It’s a rare accident” he writes, in the sense that mate preferences only rarely turn ‘sapiosexual’, focused so heavily on conspicuous displays of general intelligence… On the other hand, I think it’s likely that in any biosphere, sexual selection would eventually stumble into sapiosexual mate preferences, and then you’d get human-level intelligence and language of some sort. It might only arise in 1 out of every 100 million species though,…I suspect that in any biosphere with sexually reproducing complex organisms and a wide variety of species, you’d quite likely get at least one lineage stumbling into the sapiosexual niche within a billion years”.
A planet or moon is currently deemed potentially habitable if it orbits its parent star within the right distance range for liquid water to exist on its surface. This distance range is called the habitable zone. Since stars evolve with time, the duration of habitability is limited. Such matters can be explored through climate modeling, informed by what we know of the climates of Earth and other worlds within our solar system, and about the evolution of stars.
Current thinking is that Earth’s total duration of habitability is 6.3 to 7.8 billion years, and that our world may remain habitable for another 1.75 billion years. Since complex life has already existed on Earth for 600 million years, this seems a generous amount of time for complex life on a similar planet to stumble upon Miller’s sapiosexual niche. Stars of smaller mass than the sun are stable on longer timescales, some perhaps capable of sustaining worlds with liquid water for a hundred billion years. If Miller’s estimates are reasonable, then there may be worlds enough and time for an abundance of sapiosexual alien civilizations in our galaxy.
A central message of the METI Institute workshop is that, animals evolve whatever sort of intelligence is necessary for them to survive and reproduce under the circumstances in which they find themselves. Human-style intelligence, with language and technology, is a peculiar quirk of particular and improbable evolutionary circumstances. But we don’t know just how improbable. Given the vastness of time and number of worlds potentially available for the roll of the evolutionary dice, alien civilizations might be reasonably abundant, or they might be once-in-a-billion galaxies rare. We just don’t know. Better knowledge of the evolution of life and intelligence here on Earth might allow us to improve our estimates.
If alien civilizations do exist, what can life on Earth tell us about what their minds and senses are likely to be like? Are they, like us, visually oriented creatures, or might they rely on other senses? Can we expect that their minds might be similar enough to ours to make meaningful communication possible? These intriguing questions will be the subject of the third and final installment of this series.
Exoplanet Kepler 62f would need an atmosphere rich in carbon dioxide for water to be in liquid form. Artist's Illustration: NASA Ames/JPL-Caltech/T. Pyle
A team of astronomers suggests that an exoplanet named 62f could be habitable. Kepler data suggests that 62f is likely a rocky planet, and could have oceans. The exoplanet is 40% larger than Earth and is 1200 light years away.
62f is part of a planetary system discovered by the Kepler mission in 2013. There are 5 planets in the system, and they orbit a star that is both cooler and smaller than our Sun. The target of this study, 62f, is the outermost of the planets in the system.
Kepler can’t tell us if a planet is habitable or not. It can only tell us something about its potential habitability. The team, led by Aomawa Shields from the UCLA department of physics and astronomy, used different modeling methods to determine if 62f could be habitable, and the answer is, maybe.
According to the study, much of 62f’s potential habitability revolves around the CO2 component of its atmosphere, if it indeed has an atmosphere. As a greenhouse gas, CO2 can have a significant effect on the temperature of a planet, and hence, a significant effect on its habitability.
Earth’s atmosphere is only 0.04% carbon dioxide (and rising.) 62f would likely need to have much more CO2 than that if it were to support life. It would also require other atmospheric characteristics, .
The study modelled parameters for CO2 concentration, atmospheric density, and orbital characteristics. They simulated:
An atmospheric thickness from the same as Earth’s up to 12 times thicker.
Carbon dioxide concentrations ranging from the same as Earth’s up to 2500 times Earth’s level.
Multiple different orbital configurations.
It may look like the study casts its net pretty wide in order to declare a planet potentially habitable. But the simulations were pretty robust, and relied on more than a single, established modelling method to produce these results. With that in mind, the team found that there are multiple scenarios that could make 62f habitable.
“We found there are multiple atmospheric compositions that allow it to be warm enough to have surface liquid water,” said Shields, a University of California President’s Postdoctoral Program Fellow. “This makes it a strong candidate for a habitable planet.”
Our dear, sweet Earth is the only planet where life is confirmed. Here it is, as seen on July 6, 2015 from a distance of one million miles by a NASA scientific camera aboard the Deep Space Climate Observatory spacecraft. Credits: NASA
As mentioned earlier, CO2 concentration is a big part of it. According to Shields, the planet would need an atmospheric entirely composed of CO2, and an atmosphere five times as dense as Earth’s to be habitable through its entire year. That means that there would be 2500 times more carbon dioxide than Earth has. This would work because the planet’s orbit may take it far enough away from the star for water to freeze, but an atmosphere this dense and this high in CO2 would keep the planet warm.
But there are other conditions that would make 62f habitable, and these include the planet’s orbital characteristics.
“But if it doesn’t have a mechanism to generate lots of carbon dioxide in its atmosphere to keep temperatures warm, and all it had was an Earth-like amount of carbon dioxide, certain orbital configurations could allow Kepler-62f’s surface temperatures to temporarily get above freezing during a portion of its year,” said Shields. “And this might help melt ice sheets formed at other times in the planet’s orbit.”
Shields and her team used multiple modelling methods to produce these results. The climate was modelled using the Community Climate System Model and the Laboratoire de Me´te´orologie Dynamique Generic model. The planet’s orbital characteristics were modelled using HNBody. This study represents the first time that these modelling methods were combined, and this combined method can be used on other planets.
Shields said, “This will help us understand how likely certain planets are to be habitable over a wide range of factors, for which we don’t yet have data from telescopes. And it will allow us to generate a prioritized list of targets to follow up on more closely with the next generation of telescopes that can look for the atmospheric fingerprints of life on another world.”
There are over 2300 confirmed exoplanets, and many more candidates yet to be confirmed. Only a handful of them have been confirmed as being in the habitable zone around their host star. Of course, we don’t know if life can exist on other planets, even if they do reproduce the same kind of habitability that Earth has. We just have no way of knowing, yet.
That will change when instruments like the James Webb Space Telescope are able to peer into the atmospheres of exoplanets and tell us something about any bio-markers that might be present.
But until then, and until we actually visit another world with a probe of some design, we need to use modelling like the type employed in this study, to get us closer to answering the question of life on other worlds.
An exoplanet seen from its moon (artist's impression). Via the IAU.
Is there life on other planets, somewhere in this enormous Universe? That’s probably the most compelling question we can ask. A lot of space science and space missions are pointed directly at that question.
The Kepler mission is designed to find exoplanets, which are planets orbiting other stars. More specifically, its aim is to find planets situated in the habitable zone around their star. And it’s done so. The Kepler mission has found 297 confirmed and candidate planets that are likely in the habitable zone of their star, and it’s only looked at a tiny patch of the sky.
But we don’t know if any of them harbour life, or if Mars ever did, or if anywhere ever did. We just don’t know. But since the question of life elsewhere in the Universe is so compelling, it’s driven people with intellectual curiosity to try and compute the likelihood of life on other planets.
One of the main ways people have tried to understand if life is prevalent in the Universe is through the Drake Equation, named after Dr. Frank Drake. He tried to come up with a way to compute the probability of the existence of other civilizations. The Drake Equation is a mainstay of the conversation around the existence of life in the Universe.
The Drake Equation is a way to calculate the probability of extraterrestrial civilizations in the Milky Way that were technologically advanced to communicate. When it was created in 1961, Drake himself explained that it was really just a way of starting a conversation about extraterrestrial civilizations, rather than a definitive calculation. Still, the equation is the starting point for a lot of conversations.
But the problem with the Drake equation, and with all of our attempts to understand the likelihood of life starting on other planets, is that we only have the Earth to go by. It seems like life on Earth started pretty early, and has been around for a long time. With that in mind, people have looked out into the Universe, estimated the number of planets in habitable zones, and concluded that life must be present, and even plentiful, in the Universe.
But we really only know two things: First, life on Earth began a few hundred million years after the planet was formed, when it was sufficiently cool and when there was liquid water. The second thing that we know is that a few billions of years after life started, creatures appeared which were sufficiently intelligent enough to wonder about life.
In 2012, two scientists published a paper which reminded us of this fact. David Spiegel, from Princeton University, and Edwin Turner, from the University of Tokyo, conducted what’s called a Bayesian analysis on how our understanding of the early emergence of life on Earth affects our understanding of the existence of life elsewhere.
A Bayesian analysis is a complicated matter for non-specialists, but in this paper it’s used to separate out the influence of data, and the influence of our prior beliefs, when estimating the probability of life on other worlds. What the two researchers concluded is that our prior beliefs about the existence of life elsewhere have a large effect on any probabilistic conclusions we make about life elsewhere. As the authors say in the paper, “Life arose on Earth sometime in the first few hundred million years after the young planet had cooled to the point that it could support water-based organisms on its surface. The early emergence of life on Earth has been taken as evidence that the probability of abiogenesis is high, if starting from young-Earth-like conditions.”
A key part of all this is that life may have had a head start on Earth. Since then, it’s taken about 3.5 billion years for creatures to evolve to the point where they can think about such things. So this is where we find ourselves; looking out into the Universe and searching and wondering. But it’s possible that life may take a lot longer to get going on other worlds. We just don’t know, but many of the guesses have assumed that abiogenesis on Earth is standard for other planets.
What it all boils down to, is that we only have one data point, which is life on Earth. And from that point, we have extrapolated outward, concluding hopefully that life is plentiful, and we will eventually find it. We’re certainly getting better at finding locations that should be suitable for life to arise.
What’s maddening about it all is that we just don’t know. We keep looking and searching, and developing technology to find habitable planets and identify bio-markers for life, but until we actually find life elsewhere, we still only have one data point: Earth. But Earth might be exceptional.
As Spiegel and Turner say in the conclusion of their paper, ” In short, if we should find evidence of life that arose wholly idependently of us – either via astronomical searches that reveal life on another planet or via geological and biological studies that find evidence of life on Earth with a different origin from us – we would have considerably stronger grounds to conclude that life is probably common in our galaxy.”
With our growing understanding of Mars, and with missions like the James Webb Space Telescope, we may one day soon have one more data point with which we can refine our probabilistic understanding of other life in the Universe.
Or, there could be a sadder outcome. Maybe life on Earth will perish before we ever find another living microbe on any other world.
An artistic representation of Gliese 832 c against a stellar nebula background. A new paper says Gliese 832 might be home to another planet similar to this, but in the habitable zone. Credit: Planetary Habitability Laboratory at the University of Puerto Rico, Arecibo, NASA/Hubble, Stellarium.
Earth may have a new neighbour, in the form of an Earth-like planet in a solar system only 16 light years away. The planet orbits a star named Gliese 832, and that solar system already hosts two other known exoplanets: Gliese 832B and Gliese 832C. The findings were reported in a new paper by Suman Satyal at the University of Texas, and colleagues J. Gri?th, and Z. E. Musielak.
Gliese 832B is a gas giant similar to Jupiter, at 0.64 the mass of Jupiter, and it orbits its star at 3.5 AU. G832B probably plays a role similar to Jupiter in our Solar System, by setting gravitational equilibrium. Gliese 832C is a Super-Earth about 5 times as massive as Earth, and it orbits the star at a very close 0.16 AU. G832C is a rocky planet on the inner edge of the habitable zone, but is likely too close to its star for habitability. Gliese 832, the star at the center of it all, is a red dwarf about half the size of our Sun, in both mass and radius.
The newly discovered planet is still hypothetical at this point, and the researchers put its mass at between 1 and 15 Earth masses, and its orbit at between 0.25 to 2.0 AU from Gliese 582, its host star.
The two previously discovered planets in Gliese 832 were discovered using the radial velocity technique. Radial velocity detects planets by looking for wobbles in the host star, as it responds to the gravitational tug exerted on it by planets in orbit. These wobbles are observable through the Doppler effect, as the light of the affected star is red-shifted and blue-shifted as it moves.
The team behind this study re-analyzed the data from the Gliese 832 system, based on the idea that the vast distance between the two already-detected planets would be home to another planet. According to other solar systems studied by Kepler, it would be highly unusual for such a gap to exist.
As they say in their paper, the main thrust of the study is to explore the gravitational effect that the large outer planet has on the smaller inner planet, and also on the hypothetical Super-Earth that may inhabit the system. The team conducted numerical simulations and created models constrained by what’s known about the Gliese 832 system to conclude that an Earth-like planet may orbit Gliese 832.
This can all sound like some hocus-pocus in a way, as my non-science-minded friends like to point out. Just punch in some numbers until it shows an Earth-like planet, then publish and get attention. But it’s not. This kind of modelling and simulation is very rigorous.
Putting in all the data that’s known about the Gliese 832 system, including radial velocity data, orbital inclinations, and gravitational relationships between the planets and the star, and between the planets themselves, yields bands of probability where previously undetected planets might exist. This result tells planet hunters where to start looking for planets.
In the case of this paper, the result indicates that “there is a slim window of about 0.03 AU where an Earth-like planet could be stable as well as remain in the HZ.” The authors are quick to point out that the existence of this planet is not proven, only possible.
The other planets were found using the radial velocity method, which is pretty reliable. But radial velocity only provides clues to the existence of planets, it doesn’t prove that they’re there. Yet. The authors acknowledge that a larger number of radial velocity observations are needed to confirm the existence of this new planet. Barring that, either the transit method employed by the Kepler spacecraft, or direct observation with powerful telescopes, may also provide positive proof.
So far, the Kepler spacecraft has confirmed the existence of 1,041 planets. But Kepler can’t look everywhere for planets. Studies like these are crucial in giving Kepler starting points in its search for exoplanets. If an exoplanet can be confirmed in the Gliese 832 system, then it also confirms the accuracy of the simulation that the team behind this paper performed.
If confirmed, G832 C would join a growing list of exoplanets. It wasn’t long ago that we knew almost nothing about other solar systems. We only had knowledge of our own. And even though it was always unlikely that our Solar System would for some reason be special, we had no certain knowledge of the population of exoplanets in other solar systems.
Studies like this one point to our growing understanding of the dynamics of other solar systems, and the population of exoplanets in the Milky Way, and most likely throughout the cosmos.
NASA’s Opportunity rover discovers a beautiful Martian dust devil moving across the floor of Endeavour crater as wheel tracks show robots path today exploring the steepest ever slopes of the 13 year long mission, in search of water altered minerals at Knudsen Ridge inside Marathon Valley on 1 April 2016. This navcam camera photo mosaic was assembled from raw images taken on Sol 4332 (1 April 2016) and colorized. Credit: NASA/JPL/Cornell/ Ken Kremer/kenkremer.com/Marco Di Lorenzo
NASA’s Opportunity rover discovers a beautiful Martian dust devil moving across the floor of Endeavour crater as wheel tracks show robots path today exploring the steepest ever slopes of the 13 year long mission, in search of water altered minerals at Knudsen Ridge inside Marathon Valley on 1 April 2016. This navcam camera photo mosaic was assembled from raw images taken on Sol 4332 (1 April 2016) and colorized. Credit: NASA/JPL/Cornell/ Ken Kremer/kenkremer.com/Marco Di Lorenzo
A “beautiful dust devil” was just discovered today, April 1, on the Red Planet by NASA’s long lived Opportunity rover as she is simultaneously exploring water altered rock outcrops at the steepest slopes ever targeted during her 13 year long expedition across the Martian surface. Opportunity is searching for minerals formed in ancient flows of water that will provide critical insight into establishing whether life ever existed on the fourth rock from the sun.
“Yes a beautiful dust devil on the floor of Endeavour Crater,” Ray Arvidson, Opportunity Deputy Principal Investigator of Washington University in St. Louis, confirmed to Universe Today. Spied from where “Opportunity is located on the southwest part of Knudsen Ridge” in Marathon Valley.
The new dust devil – a mini tornado like feature – is seen scooting across the ever fascinating Martian landscape in our new photo mosaic illustrating the steep walled terrain inside Marathon Valley and overlooking the crater floor as Opportunity makes wheel tracks at the current worksite on a crest at Knudsen Ridge. The colorized navcam camera mosaic combines raw images taken today on Sol 4332 (1 April 2016) and stitched by the imaging team of Ken Kremer and Marco Di Lorenzo.
“The dust devils have been kind to this rover,” Jim Green, Director of NASA Planetary Sciences at NASA HQ, said in an exclusive interview with Universe Today. They are associated with prior periods of solar array cleansing power boosts that contributed decisively to her longevity.
“Oppy’s best friend is on its way!”
Spotting dust devils has been relatively rare for Opportunity since landing on Mars on Jan. 24, 2004.
“There are 7 candidates, 6 of which are likely or certain,” Mark Lemmon, rover science team member from Texas A & M University, told Universe Today. “Most were seen in, on the rim of, or adjacent to Endeavour.”
Starting in late January, scientists commanded the golf cart sized Opportunity to drive up the steepest slopes ever attempted by any Mars rover in order to reach rock outcrops where she can conduct breakthrough science investigations on smectite (phyllosilicate) clay mineral bearing rocks yielding clues to Mars watery past.
“We are beginning an imaging and contact science campaign in an area where CRISM spectra show evidence for deep absorptions associated with Fe [Iron], Mg [Magnesium] smectites,” Arvidson explained.
A shadow and tracks of NASA’s Mars rover Opportunity appear in this March 22, 2016, image, which has been rotated 13.5 degrees to adjust for the tilt of the rover. The hillside descends to the left into “Marathon Valley.” The floor of Endeavour Crater is seen beneath the underside of a solar panel. Credits: NASA/JPL-Caltech
This is especially exciting to researchers because the phyllosilicate clay mineral rocks formed under water wet, non-acidic conditions that are more conducive to the formation of Martian life forms – billions of years ago when the planet was far warmer and wetter.
“We have been in the smectite [phyllosilicate clay mineral] zone for months, ever since we entered Marathon Valley.”
The smectites were discovered via extensive, specially targeted Mars orbital measurements gathered by the CRISM (Compact Reconnaissance Imaging Spectrometer for Mars) spectrometer on NASA’s Mars Reconnaissance Orbiter (MRO) – accomplished earlier at the direction of Arvidson.
So the ancient, weathered slopes around Marathon Valley became a top priority science destination after they were found to hold a motherlode of ‘smectite’ clay minerals based on the CRISM data.
“Marathon Valley is unlike anything we have ever seen. Looks like a mining zone!”
At this moment, the rover is driving to an alternative rock outcrop located on the southwest area of the Knudsen Ridge hilltops after trying three times to get within reach of the clay minerals by extending her instrument laden robotic arm.
NASA’s Opportunity rover images current worksite at Knudsen Ridge on Sol 4228 where the robot is grinding into rock targets inside Marathon Valley during 12th Anniversary of touchdown on Mars in Jan. 2016. Credit: NASA/JPL/Cornell/Marco Di Lorenzo/Ken Kremer/kenkremer.com
Unfortunately, but not unexpectedly, the rover kept slipping on the steep walled slopes – tilted as much as 32 degrees – while repeatedly attempting close approaches to the intended target. Ultimately she came within 3 inches of the surface science target ‘Pvt. Joseph Whitehouse’ – named after a member of the Corps of Discovery.
In fact despite rotating her wheels enough to push uphill about 66 feet (20 meters) if there had been no slippage, engineers discerned from telemetry that slippage was so great that “the vehicle progressed only about 3.5 inches (9 centimeters). This was the third attempt to reach the target and came up a few inches short,” said NASA.
“The rover team reached a tough decision to skip that target and move on.”
So they backed Opportunity downhill about 27 feet (8.2 meters), then drove about 200 feet (about 60 meters) generally southwestward and uphill, toward the next target area.
NASA officials noted that “the previous record for the steepest slope ever driven by any Mars rover was accomplished while Opportunity was approaching “Burns Cliff” about nine months after the mission’s January 2004 landing on Mars.”
Marathon Valley measures about 300 yards or meters long. It cuts downhill through the west rim of Endeavour crater from west to east – the same direction in which Opportunity is currently driving downhill from a mountain summit area atop the crater rim. See our route map below showing the context of the rovers over dozen year long traverse spanning more than the 26 mile distance of a Marathon runners race.
Endeavour crater spans some 22 kilometers (14 miles) in diameter. Opportunity has been exploring Endeavour since arriving at the humongous crater in 2011.
NASA’s Opportunity rover peers outwards across to the vast expense of Endeavour Crater from current location descending along steep walled Marathon Valley in early November 2015. Marathon Valley holds significant deposits of water altered clay minerals holding clues to the planets watery past. Shadow of Pancam Mast assembly and robots deck visible at right. This navcam camera photo mosaic was assembled from images taken on Sol 4181 (Oct. 29, 2015) and colorized. Credit: NASA/JPL/Cornell/Ken Kremer/kenkremer.com/Marco Di Lorenzo
Why are the dust devils a big deal?
Offering more than just a pretty view, the dust devils actually have been associated with springtime Martian winds that clear away the dust obscuring the robots life giving solar panels.
“Opportunity is largely in winter mode sitting on a hill side getting maximum power. But it is in a better power status than in many past winters,” Jim Green, Director of NASA Planetary Sciences at NASA HQ, told Universe Today exclusively.
“I think I know the reason. As one looks across the vistas of Mars in this mosaic Oppys best friend is on its way.”
“The dust devils have been kind to this rover. Even I have a smile on my face when I see what’s coming.”
12 Year Traverse Map for NASA’s Opportunity rover from 2004 to 2016. This map shows the entire path the rover has driven during almost 12 years and more than a marathon runners distance on Mars for over 4332 Sols, or Martian days, since landing inside Eagle Crater on Jan 24, 2004 – to current location at the western rim of Endeavour Crater and descending into Marathon Valley. Rover surpassed Marathon distance on Sol 3968 and marked 11th Martian anniversary on Sol 3911. Opportunity discovered clay minerals at Esperance – indicative of a habitable zone – and is currently searching for more at Marathon Valley. Credit: NASA/JPL/Cornell/ASU/Marco Di Lorenzo/Ken Kremer/kenkremer.com
As of today, Sol 4332, Apr. 1, 2016, Opportunity has taken over 209,200 images and traversed over 26.53 miles (42.69 kilometers) – more than a marathon.
The power output from solar array energy production has climbed to 576 watt-hours, now just past the depths of southern hemisphere Martian winter.
Meanwhile Opportunity’s younger sister rover Curiosity traverses and drills into the basal layers at the base of Mount Sharp.
This March 21, 2016, image from the navigation camera on NASA’s Mars rover Opportunity shows streaks of dust or sand on the vehicle’s rear solar panel after a series of drives during which the rover was pointed steeply uphill. The tilt and jostling of the drives affected material on the rover deck. Credits: NASA/JPL-Caltech
Stay tuned here for Ken’s continuing Earth and planetary science and human spaceflight news.
Learn more about NASA Mars rovers, Orion, SLS, ISS, Orbital ATK, ULA, SpaceX, Boeing, Space Taxis, NASA missions and more at Ken’s upcoming outreach events:
Apr 9/10: “NASA and the Road to Mars Human Spaceflight programs” and “Curiosity explores Mars” at NEAF (NorthEast Astronomy and Space Forum), 9 AM to 5 PM, Suffern, NY, Rockland Community College and Rockland Astronomy Club – http://rocklandastronomy.com/neaf.html
Apr 12: Hosting Dr. Jim Green, NASA, Director Planetary Science, for a Planetary sciences talk about “Ceres, Pluto and Planet X” at Princeton University; 7:30 PM, Amateur Astronomers Assoc of Princeton, Peyton Hall, Princeton, NJ – http://www.princetonastronomy.org/
Apr 17: “NASA and the Road to Mars Human Spaceflight programs”- 1:30 PM at Washington Crossing State Park, Nature Center, Titusville, NJ – http://www.state.nj.us/dep/parksandforests/parks/washcros.html
A shadow and tracks of NASA’s Mars rover Opportunity appear in this March 22, 2016, colorized hazcam camera image, which has been rotated 13.5 degrees to adjust for the tilt of the rover. The hillside descends to the left into “Marathon Valley.” The floor of Endeavour Crater is seen beneath the underside of a solar panel. Credits: NASA/JPL-Caltech/Marco Di Lorenzo/Ken Kremer/kenkremer.comComposite hazcam camera image (left) shows the robotic arm in motion as NASA’s Mars Exploration Rover Opportunity places the tool turret on the target named “Private John Potts” on Sol 4234 to brush away obscuring dust. Rover is actively working on the southern side of “Marathon Valley” which slices through western rim of Endeavour Crater. On Sol 4259 (Jan. 16, 2016), Opportunity completed grinds with the Rock Abrasion Tool (RAT) to exposure rock interior for elemental analysis, as seen in mosaic (right) of four up close images taken by Microscopic Imager (MI). Credit: NASA/JPL/Cornell/Ken Kremer/kenkremer.com/Marco Di Lorenzo
Lasers like this one, at the VLT in Paranal, help counteract the blurring effect of the atmosphere. Powerful arrays of much larger lasers could hide our presence from aliens. (ESO/Y. Beletsky)
Of course we all know that aliens want to take over Earth. It’s in all the movies. And after they take over, they could do whatever they want to us puny, weak Earthlings. Enslavement? Yup. Forced breeding programs? Sure. Lay eggs in our bellies and consume our guts for their first meal? Why not.
But here at Universe Today, we’re science-minded types. We love the science fiction, but don’t take it too seriously. But someone we do take seriously when he has something to tell us is Stephen Hawking. And when he warned us that aliens might want to conquer and colonize us, it lent gravity to the whole discussion around contact with aliens. Should we reach out to alien civilizations? Will we be safe if they find us? Or should we try to conceal our presence?
If we choose concealment, then a new paper from two astronomers at New York’s Columbia University have good news for humanity. The authors of the paper, Professor David Kipping and graduate student Alex Teachey, say that lasers could be used to hide Earth from alien prying eyes.
At the heart of this whole idea are transits. When a planet passes in between its star and a distant observer, the star’s light is dimmed, and that’s called a transit. This is how the Kepler spacecraft detects exo-planets, and it’s been remarkably successful. If alien species are using the same method, which makes sense, then Earth would be easily detectable in the Sun’s habitable zone.
According to Kipping and Teachey, lasers could be used to mask this effect. A 30 MW laser would be enough to counter the dimming effect of Earth’s transit in front of the Sun. And it would only need to be turned on for 10 hours, once every year, since that’s how long Earth’s transit takes.
But that would only take care of the dimming effect in visible light. To counter-act the transit dimming across the whole electromagnetic spectrum would require much more energy: a 250 MW cloak of lasers tuned all across the spectrum. But there might be a middle way.
According to an interview with the paper’s authors in Science Daily, it might take only 160 MW of lasers to mask biological signatures in the atmosphere. Any prying alien eyes would not notice that life had ever come into being on Earth.
Should we decide that we do indeed want to be colonized, or forced to take part in breeding programs, or be enslaved, then the same system of lasers could be used to amplify the transit effect. This would make it easier, rather than harder, for aliens to detect us. In fact, according to the authors, these lasers could even be used to communicate with aliens, by transmitting information.
Of course, there’s one other element to all this. For this to work, we have to know where to aim the lasers, which means we have to know where the alien civilization is. And if we’re worried about them coming to get us, they will have more advanced technology than us. And if they have more advanced technology than us, they will for sure already have laser cloaking like the type talked about here.
So who’ll be the first to blink, and turn off their laser cloaking and allow detection?
