(Photo: Jeremy Burgin via Flickr/Creative Commons)
Many of us believe finding some form of life beyond our own planet is inevitable, and the recent discovery of Earth-like planets – in a region where liquid water could exist on a planet’s surface – has renewed excitement about eventually finding extra-terrestrial life.
However, two Princeton University researchers suggest those expectations may be more based in optimism rather than scientific fact.
So they took what science currently knows about the existence, or likelihood of extra-terrestrial life, and performed a Bayesian analysis, which evaluates just how much of what is considered to be a scientific conclusion comes from actual hard scientific fact and what comes from assumptions made by the scientist involved.
What the duo found will disappoint those counting on meeting ET.
In a paper published in Proceedings of the National Academy of Sciences, Turner and Spiegel report finding little supporting scientific evidence that life exists, or could exist, beyond our own planet.
Instead, they found that most of what has been concluded about the possibility of extra-terrestrial life has been taken from what scientists know about the origins or emergence of life on early Earth. And that our expecting life to be found on Earth-like exoplanets mostly centers on the assumption of what could or would happen if conditions similar to those that allowed life on Earth to flourish were found elsewhere.
Taking what we already know about life on other planets, the researchers say it’s very possible Earth may be an oddity compared to other planets, because life took root quickly and early in our planet’s history. If this is true, then the chances of Earth-like planets hosting life would be low.
“If scientists start out assuming that the chances of life existing on another planet as it does on Earth are large, then their results will be presented in a way that supports that likelihood,” Turner said. “Our work is not a judgment, but an analysis of existing data that suggests the debate about the existence of life on other planets is framed largely by the prior assumptions of the participants.”
So what do you think? Are our current expectations of finding life out there in the cosmos based on scientific fact or on mere optimism as suggested by the authors of this study?
Coils of Lava Found on Mars
This image, with more than a dozen lava coils visible, shows an area in a volcanic region named Cerberus Palus that is about 500 meters wide. (Photo: NASA/JPL/University of Arizona)
An Arizona State University graduate student has discovered unique spiral patterns in solidified lava flows on the surface of Mars.
In a paper published in Science, Andrew Ryan describes the snail-like patterns as ranging in size from about one meter to 30 meters across.
While lava flows such as these have been found on the Big Island of Hawaii and near the Galapagos Rift on the Pacific Ocean floor, Ryan says they’ve never been detected on Mars before.
Ryan was originally doing research into possible interactions of lava flows with floods of water in the Elysium volcanic province located near the Mars equator.
Some of the features of this Martian volcanic region include what has been described as large slabs or plates of volcanic rock that look like the broken floes of pack ice that can be found in Earth’s Arctic Ocean.
For several years, scientists have theorized there was a frozen ocean in that region, and that the physical appearance of the volcanic plate’s chunks of ice floe may be caused by ice that lies beneath them.
It was these claims of ice that drew Ryan to focus his research on that area of Mars.
Newer lava lying between two older plates of rough, hardened lava was still hot and plastic enough to form coils and spirals when the plates slid past one another. This image shows an area about 360 meters wide in Cerberus Palus. (Photo: NASA/JPL/University of Arizona)
Ryan was fascinated by the terrain that lies between the plates and the high-centered polygonal patterns that were found there.
That led him to examine images of the region captured by the various Martian probes circling the planet.
After scrutinizing almost 100 images, Ryan determined that the various landforms, including the lava flow coils, that he saw were indeed volcanic and not ice related.
His findings confirmed what he and his colleagues had thought all along.
“This region is very close to the Martian equator and we don’t expect to find near-surface ice that close to the equator,” Ryan says.
As to how the lava flows coils themselves were formed, Ryan explains, “The coils form on flows where there’s a shear stress — where flows move past each other at different speeds or in different directions. Pieces of rubbery and plastic lava crust can either be peeled away and physically coiled up — or wrinkles in the lava’s thin crust can be twisted around.”
Once some numerical modeling has been done, Ryan says that it might be possible to learn a bit about the composition of the lava that formed the coils.
He also plans to do further research which he hopes will help determine the viscosity, or thickness, of the lava while it was solidifying and forming the coils.
Andrew Ryan joins us on this week’s radio edition of Science World to talk about his discovery, as well as the research and study he conducted to back-up his findings. Tune in (see right column for scheduled times) or check out the interview below.
[audio://blogs.voanews.com/science-world/files/2012/04/One-On-One-Andrew-Ryan-Lava-Coils-on-Mars.mp3|titles=One On One – Andrew Ryan – Lava Coils on Mars]
Other stories we cover on the “Science World” radio program this week include:
Titanic Director Backs Venture to Mine Platinum from Asteroids
This computer-generated image shows a conceptual rendering of a Planetary Resources spacecraft preparing to capture a water-rich, near-Earth asteroid. (AP/Planetary Resources)
What do filmmaker and deep sea explorer, James Cameron, and Google co-founder, Larry Page, have in common?
The firm that plans to turn what sounds like science fiction into science fact is called Planetary Resources of Seattle, Washington.
In a press release announcing the venture, the company says a single 500-meter platinum-rich asteroid could contain the equivalent of all the platinum group metals (ruthenium, rhodium, palladium, osmium, iridium, and platinum) that have ever been mined on Earth.
Along with mining precious metals, the company also hopes to take advantage of water-rich asteroids, which they hope will function as “stepping stones” for future deep space exploration.
The water will be used to provide various life supporting functions, such drinking water and breathable air, as well as to help make rocket fuel.
This computer-generated image shows a conceptual rendering of satellites prospecting a water-rich, near-Earth asteroid. (AP/Planetary Resources)
The way Planetary Resources sees it, providing water, air and fuel at these space-based “pit stops” will revolutionize space exploration and make space travel much more economical.
To get the project moving, Planetary Resources has developed a new line of space craft which will initially be used to survey the targeted asteroids for resources. Later, the vehicles will extract water and metals from the asteroids.
The first of these vehicles will launch within 24 months, according to Eric Anderson, company co-founder and co-chairman.
Meanwhile, NASA is also planning a mission to a near-Earth asteroid. The U.S. space agency won’t be mining for precious metals, but it does plan to extract and return at least a 60-gram sample of the asteroid to Earth.
Currently scheduled to launch 2016 and return with the sample in 2023, the NASA mission is expected to cost approximately $800 million.
Mystery Objects Spotted Piercing Saturn’s Ring
A NASA space probe studying Saturn recently treated scientists to a bit of a surprise – rather odd little objects piercing in and out the planet’s F Ring, leaving a glittering trail of mini-jets behind.
The objects appear to travel in packs, producing multiple mini-jets which look like the barb of a harpoon.
Scientists already knew somewhat large objects can create channels, ripples and snowballs, or clumps of icy material, within the F ring. What they didn’t know was what happened to these objects after they were created. Scientists thought some of these “snowballs” were broken up into smaller pieces by collisions or tidal forces as they orbited in the F ring around Saturn.
These images, from NASA's Cassini spacecraft, show trails which were dragged out from Saturn's F ring by objects that are about one kilometer in diameter. (Photo: NASA/JPL-Caltech/SSI/QMUL ) (Click image for larger view)
Finding the mystery objects suggests scientists now have proof some of the smaller chunks of those collisions survived and, because they were set into varying orbits, these little objects went on to break through the F ring on their own.
To make their findings, scientists carefully went through about 20,000 images produced during the seven years the Cassini space probe has been at Saturn. So far, about 500 of these weird little objects have been found.
“I think the F ring is Saturn’s weirdest ring, and these latest Cassini results go to show how the F ring is even more dynamic than we ever thought,” said Carl Murray, a Cassini imaging team member.
The F ring, Saturn’s outermost main ring, has a circumference of 881,000 kilometers and is considered the most active ring in the Solar System, since its features tend to change over a period of hours.
Saturn’s rings are mostly made of ice with an average thickness of about 10 meters. The pieces of ice that make up the main rings spread out some 140,000 kilometers from the center of the planet.
The Cassini space probe’s next notable encounter will be a flyby past Saturn’s moon, Enceladus, on May 2.
Brain Blood Flow Changes Could Trigger Brain Freeze, Migraines
Owwwww! How could something that taste's so good... hurt so bad? (Photo: Jayel Aheram via Flickr/Creative Commons)
You’ve got a delicious ice cream cone in your hand and you can’t wait to taste it. You quickly take a big bite out of the frozen treat when – BANG – you get this incredibly intense shooting pain in your head.
Some call it an ice cream headache or brain freeze. Although it can be painful, we’re also comforted to know that it passes quickly.
Past research has shown that those who suffer from migraine headaches tend to get brain freeze more often than those who don’t.
That led an international team of researchers, who study migraines and other types of headaches, to wonder if there’s a common link between brain freeze and migraines.
With this connection in mind, and because they found it difficult to study migraine headaches directly, due to their unpredictability, the researchers decided to focus their study on brain freeze to gain insight into migraines and other more serious headaches.
Thirteen healthy adults were used as test subjects. As the subjects drank ice-cold water to give themselves brain freeze, researchers monitored the blood flow to their brain.
Researchers found one artery in particular, called the anterior cerebral artery, expanded rapidly when the test subjects experienced pain from the onset of brain freeze. This caused the brain to be flooded with blood. As the pain ebbed, the same artery quickly constricted, reducing the flow of blood to the brain.
From these findings, team leader Dr. Jorge Serrador, of the US Department of Veteran’s Affairs, and his fellow researchers, speculate that the rapid expansion, and then constriction, of the artery might be some sort of self-defense mechanism for the brain.
“The brain is one of the relatively important organs in the body, and it needs to be working all the time,” Serrador says. “It’s fairly sensitive to temperature, so vasodilation might be moving warm blood inside tissue to make sure the brain stays warm. But because the skull is a closed structure, the sudden influx of blood could raise pressure and induce pain. The following vasoconstriction may be a way to bring pressure down in the brain before it reaches dangerous levels.”
Serrador thinks the changes in brain blood flow observed in the study, could also be at work in serious headaches such as migraines and post-traumatic headaches.
If the study findings are confirmed by further study, new treatments that control the blood flow to the brain could be developed to help those who suffer from serious headaches such as migraines.
Running Down Body’s Internal Clock Can Make You Sick
(Photo: Bernard Wee via Flickr)
Our internal body clock may play a role in determining whether we get sick or not, according to a recent study from Yale University.
Any disruption to our body’s 24-hour clock, such as not having enough sleep, can cause it to run down, leaving us susceptible to infection and illness.
Our internal circadian clock is a well-regulated biological process which helps keep our bodies healthy and working by regulating tasks such as sleeping, waking, hormone release, body temperature and other important bodily functions throughout the course of a 24-hour cycle.
The Yale researchers, experimenting with mice, found that the circadian clock, working at the genetic level, controls an important immune system gene that goes to work when harmful bacteria and viruses are around.
The scientists discovered that vaccinating their test mice at times when levels of a genetic protein, called the toll-like receptor 9 (TLR-9), were highest provided the greatest amount of immune system response, making the vaccination more effective and allowing the mice to better resist infection.
(Image: Alison Young via Flickr)
Adam Silver, one of the study’s authors, describes the toll-like receptor as a pathogen recognition receptor (PRR) whose job is to recognize specific microbial components on either bacteria or viruses. Once these bacterial or viral components are caught by the TLR, it triggers a massive response, which leads the body to kick into an essentially antimicrobial state by producing inflammation to help remove the infection.
Since our circadian clock causes the levels of this protein to rise and fall throughout the 24-hour cycle, Silver says it’s possible there are certain times of the day when we would be more susceptible to infection.
The research team says its findings suggest, for example, that jet lag may help make us sick when we’re traveling and allow us to know the best times of day to get vaccinated.
Adam Silver talks more about his team’s research on this week’s radio edition of Science World. Tune in (see right column for scheduled times) or check out the interview below.
[audio://blogs.voanews.com/science-world/files/2012/04/One-On-One-Adam-Silver-Circadian-Clock-Influence-on-Immune-system.mp3|titles=One On One – Adam Silver – Circadian Clock Influence on Immune system]
Other stories we cover on the “Science World” radio program this week include:
Boy checks on his steak (Photo: woodleywonderworks via Flickr/Creative Commons)
Vegetarians and animal right groups may take issue with this, but a new study has revealed that when humans started to include meat in their diets, mothers were able to wean their children earlier, which allowed them to have more children, which in turn helped the human species spread throughout the world.
Researchers from Lund University in Sweden, conducting a comparison study of 67 mammalian species that included humans, apes, mice, and killer whales and others, say they found a solid connection between meat eating and shorter periods of weaning their offspring.
“Eating meat enabled the breast-feeding periods and thereby the time between births to be shortened,” said Elia Psouni, a clinical psychologist and the study’s lead author. “This must have had a crucial impact on human evolution.”
Compared to the mostly plant-eating chimpanzee, man’s closest evolutionary cousin, the study showed that humans tend to breastfeed their young for a shorter average duration, despite having nearly twice the maximum lifespan. Female chimpanzees breastfeed their young for four-to-five years, but humans only do so for an average of two years and four months.
Over the years, a number of researchers tied the human’s relatively shorter breastfeeding period to other aspects such as social and behavioral theories of parenting along with family size.
But this new research shows that breastfeeding for all species generally ends once the brains of the young reach a certain stage of development.
For their study, the Swedish researchers categorized the species into three categories: carnivores, or species whose diets take at least 20 percent of their energy content from meat, herbivores, or species whose diets only consist of plant life, and omnivores, or species who take their nourishment from both plant life and meat. For this study, the authors considered humans carnivores, despite that human diets often consist of both plant life and meat.
In comparing the weaning times for humans to the great apes such as gorillas, orangutans and chimpanzees, the researchers say that the differences seem to come down to the differences in diet composition.
“That humans seem to be so similar to other animals can of course be taken as provocative,” Psouni says. “We like to think that culture makes us different as a species. But when it comes to breast-feeding and weaning, no social or cultural explanations are needed; for our species as a whole it is a question of simple biology.”
Psouni did emphasize that the results of her study only provided insight into how the addition of meat to their diets may have contributed to early humans spreading on Earth, and that it doesn’t advocate whether humans should or should not eat meat.
Artist conception of a captured world drifting at the outer edge of a distant star system, so far from its sun-like host the star's disk is barely resolvable at upper right. (Image: Christine Pulliam, Center for Astrophysics)
Like sports teams swapping players, billions of stars within our own galaxy may have traded planets which once wandered freely throughout the galaxy in interstellar space with each other.
Those findings, from a new study, could explain why some planets within a solar system have an orbit far from their host stars. The study’s authors believe it could also explain the existence of double-planet systems – two astronomical objects that can be technically considered planets and are close enough to each other to have a substantial gravitational influence on each other compared to the effect of the star(s) they orbit.
In many cases, scientists say these rogue planets are created as a byproduct of a star’s formation. Newly-formed solar systems tend to have a number of planets, and if any of these planets interact with each other as they’re finding their place within the star system, one of those planets can be kicked out and becomes a nomad.
If, during its travels, it should happen to come across another star moving in the same direction and at the same speed, the traveling planet could attach itself to that star’s solar system.
However, some of these rogue planets may not be castaways from other solar systems, but instead could have been created independently, similar to how stars are formed. The International Astronomical Union (IAU) calls these particular planetary objects “sub-brown dwarfs.”
Artist's impression of what a rogue double system of planetary objects might look like. While the two planetary objects do not orbit around a star, they do appear to circle each other instead. (Image: ESO)
Rogue planets that become part of another solar system tend to be on the very edge of the solar system, have a unique orbit, and revolve around their adopted star in an opposite direction of the other “native planets.”
Drs. Perets and Kouwenhoven created simulations of young star clusters that also had “free-floating planets.” The researchers determined that if the number of stars and rogue planets were equal, then between three-to-six percent of those stars would nab one of the rogue planets over time. They also noted that, the more massive the star, the more likely it was to grab a wandering planet.
The researchers chose to study young star clusters because they found the seizure of rogue planets is more likely when both the stars and the “free-floating planets” are jammed in a small space.
These star clusters tend to scatter away from each other after a period of time. The scientists figured if any inter-system swapping of planets is to be done, it has to happen early in the cluster’s history.
Astronomers haven’t found any specific cases of captured planets so far.
It could be tough to determine whether they’ve spotted an actual captured rogue planet, or if it is a native planet mimicking the behavior of a rogue planet due to various gravitational interactions within its solar system.
Study Shows Gulf Oil Spill Harmed Deep-sea Coral
The Deep Submergence Vehicle, Alvin, working at the coral site impacted by the oil spill in the Gulf of Mexico. (Photo: courtesy of Chuck Fisher of Penn State University and Timothy Shank of WHOI; deep-sea time-lapse camera system provided by WHOI-MISO)
The study finds that coral communities about 11 kilometers from the spill site, and approximately 1310 meters below the water’s surface, are covered with a thick brown substance. It was found to be a mixture of dying tissue, oil, mucous excretions from the coral and other various adhering particles.
More distant coral communities examined by the research team show no signs of similar damage and appear mostly unharmed.
The multi-disciplinary research team included a number of specialists in sciences such as geology, biology, ecology and taxonomy.
The team also relied on geochemists, who were able to “finger-print” and identify the hydrocarbons found on the affected coral and in the surrounding ocean sediment.
The first cruise sailed in late October 2010, about six months after the Deepwater Horizon oil spill. After finding initial evidence of coral damage, researchers planned a second trip to the gulf. They set sail again in December 2010, barely a month after the first cruise arrived home.
Researchers had a variety of sophisticated tools to work with.
The three-passenger, robotic-armed, US Navy-owned and Woods Hole operated submersible, Alvin, provided researchers with a closer look at the deep-water coral on the mission’s second trip.
One of the impacted corals with attached brittle starfish. Although the orange tips on some branches of the coral is the color of living tissue, it is unlikely that any living tissue remains on this animal. (Photo: Lophelia II 2010, NOAA OER and BOEMRE)
Fisher considers their findings significant in several different ways. He says it’s the only study to document damage to big animals on the sea floor.
Fisher points out the study demonstrates that the Deepwater Horizon oil spill did impact a deep-sea community that harbors more than just coral some 11 kilometers away from the spill site, which he says is further than some of the other published estimates.
Also significant, says Fisher, is that the findings extended the range of the impact. He suggests continued research and investigation must be done to define the “footprint” of the spill’s impact.
Although the research looked at one close-in site, Fisher feels there are undoubtedly other deep-sea coral sites in the region that should be studied.
Fisher’s team is continuing its research and investigating similar coral communities.
On this week’s radio edition of “Science World”, Charles Fisher talks about the research expedition’s results. Tune in (see right column for scheduled times) or check out the interview below.
[audio://blogs.voanews.com/science-world/files/2012/04/One-on-One-Charles-Fisher-Oil-Spill-Impact-on-Coral.mp3|titles=One on One – Charles Fisher – Oil Spill Impact on Coral]
Other stories we cover on the “Science World” radio program this week include:
Experts theorize about 80 percent of matter in the universe can’t be seen by telescopes.
But they know something is there because of its gravitational influence over the orbital speeds of stars around galaxies and how clusters of galaxies move within the universe.
This so-called “dark matter” forms most of the universe, yet it neither gives off nor absorbs light or any other electromagnetic radiation.
This dwarf spheroidal galaxy in the constellation Fornax is a satellite of our Milky Way and is one of 10 used in Fermi's dark matter search. (Photo: ESO/Digital Sky Survey 2)
Scientists think the key to its identity will be the discovery of new types of subatomic particles that are quite different from those that make up the atoms of visible and known matter that surrounds us.
Among the new particles scientists have favored to form dark matter are those called “Weakly Interacting Massive Particles” or WIMPS. Scientists think some of these particles are destroyed when pairs of them interact with each other, producing gamma rays – the most energetic form of light – at the same time.
With this in mind, the team set out to see if the gamma ray signals from 10 dwarf galaxies are consistent with the high-energy radiation produced from the destruction of four different types of WIMP particles, thought to be associated with dark matter.
Rather than analyzing each of the galaxies separately, the scientists developed a statistical technique that allowed them to evaluate all of the galaxies at once.
The analysis showed none of the gamma ray signals they studied are consistent with those that could be produced by these four classes of WIMP particles and therefore could not be dark matter.
So, as scientists continue their investigation into dark matter, at least they now have four classes of WIMP particles that have been eliminated from consideration.
