Filled Under: Possible Alien
SETI is stepping up its search for alien lifeforms on far off worlds.
The Search for Extraterrestrial Intelligence (SETI) program recently announced two new methods to search for signals that could come from life on other planets. In the Panchromatic SETI project, multiple telescopes will scan a variety of wavelengths from 30 stars near the sun; the project will look for powerful signals beamed into space, potentially by intelligent extraterrestrials. SETI is also launching an interplanetary eavesdropping program that is expected to search for messages beamed between planets in a single system.
“If we are polluting space, perhaps other extraterrestrials are leaking signals,” Dan Werthimer, director of the Berkley SETI Center, told an audience during the Smithsonian Magazine’s “The Future is Here” Festival in May. “Maybe they’re sending something our way.” [10 Exoplanets That Could Host Alien Life]
‘Everything we’ve got’
Since humans made their first FM radio and television transmissions, signals from Earth have been spilling out into space, announcing the presence of intelligent life to any group that might be searching for it. According to Werthimer, signals from the 1950s television show “I Love Lucy” have reached thousands of stars, while the nearest suns have already enjoyed the “The Simpsons.”
If Earth has unintentionally leaked signs of its presence, other alien civilizations may have done the same thing. SETI’s new Panchromatic project will utilize a variety of telescopes covering a range of frequencies to scour the nearest stars.
“We’re going to throw everything we’ve got at it,” Werthimer added.
The panchromatic project will examine a sample of the 30 stars that lie within 5 parsecs (16 light-years) from the sun. The list includes 13 single stars, seven binary systems and one triple system. Most of the stars are smaller than the sun, but the project will also examine two white dwarfs and one moderately evolved F star. No confirmed exoplanets have been found around any of the stars.
By setting distance as the criteria, the SETI team hopes to alleviate any bias that might otherwise result from focusing on systems similar to that of Earth. The team selected stars for based only on how far they lie from the sun.
According to SETI-Berkeley’s Andrew Siemion, chief scientist of the eavesdropping project, the search will also probe a diverse stellar population already well studied at many wavelengths.
Observations from the Low Frequency Array (LOFAR) telescope in Europe and the Green Bank Telescope (GBT) in West Virginia will begin over the summer and fall of 2014. Instrument development and commissioning is still in progress for the Infrared Spatial Interferometer (ISI) at Mount Wilson Observatory and the Nickel Telescope at Lick Observatory, both in California. But according to Siemion, the pair should be ready at about the same time. The Nickel Telescope will conduct the first-ever SETI observations done in the near-infrared.
The project has also proposed time on the William E. Gordon telescope at Arecibo Observatory in Puerto Rico, and hopes to piggyback on observations obtained at the Keck Telescope in Mauna Kea, Hawaii.
“Pending availability, we also intend to observe our initial panchromatic target list with other telescopes,” Siemion said.
The close distances of the stars selected for the Panchromatic project should make potential signals from intelligent civilizations easier to detect, Siemion said.
“Within a couple of parsecs, E.T. wouldn’t have to have technology much more advanced than ours in order for us to detect it,” Siemion said. [5 Bold Claims of Alien Life]
Signals from E.T.’s rovers
The second SETI project will make use of the observations of multi-planet systems gathered by NASA’s Kepler mission as it attempts to eavesdrop on signals broadcast from one planet to another.
The Kepler telescope detects planets as they pass in front of their stars, causing a dip in the stars’ brightness. If two planets lie in the same orbital plane, pointed toward Earth, they will occasionally line up. If an intelligent species originated on one planet in a system, then went on to explore or inhabit a second planet, signals sent from one planet to the other should be detectable when the two are lined up facing the Earth.
So far, the team has observed about 75 of these events in multi-planet systems using the Green Bank Telescope. The range of radio frequencies include those used on Earth to with craft sent to other planets.
“Our detection algorithms are sensitive to communications like those used by NASA’s Deep Space Network to communicate with spacecraft, so if E.T. broadcasts something similar at sufficient power, we could hear it,” Siemion said.
Detecting such signals doesn’t necessarily mean researchers will be able to translate them. Scientists may not be able to determine if the is to an outpost or a rover. However, that won’t make the discovery any less exciting.
Though a signal between planets should be detectable, Siemion said that it is more likely that a broad signal would be intercepted. Although terrestrial television broadcasts in large beams, these would be too weak to detect under the current experiments. Instead, scientists would be looking for something like the U.S. Air Force’s “sky fence,” a high-frequency radar used in an attempt to track space junk in orbit.
Distance poses one of the biggest problems in eavesdropping on extraterrestrials. The required power for a transmitter to be detected increases with the square of the distance. A transmitter 150 light-years away would need to be 100 times as powerful as one 15 light-years away, if everything else remains the same.
Most of the Kepler planets and planetary candidates lie at significant distances from Earth, making it difficult for scientists to detect weaker signals like those emitted by spacecraft communication. However, if alien civilizations used something akin to Arecibo, Siemion said, scientists would stand a far better chance of detecting it.
“The flood of multiplanet systems discovered by Kepler and the high precision of the planetary ephemerides the Kepler team publishes has directly made this experiment possible,” Siemion said. Ephemerides are tables that provide the positions of astronomical bodies at a given time.
He expressed his excitement about NASA’s planned Transiting Exoplanet Survey Satellite (TESS) mission, set to launch in 2017.
“TESS will find lots of multiplanet systems as well, but they will be closer to Earth,” said Siemion.
Astronomers also look forward to using the Square Kilometer Array (SKA), which could be more than an order of magnitude more sensitive than current systems and thousands of times faster.
The explosion in discoveries of planets and planetary candidates over the past two decades has provided a strong encouragement for SETI’s search for intelligent life, Siemion said.
“If there is one message from exoplanet research in the last two decades, it is that, , planets are everywhere,” he said. “Moreover, rocky, lukewarm planets appear to be very common. We shouldn’t have to look very far, statistically speaking, to find planets where life could develop.”
Is eating DNA safe?
Eating DNA sounds scary but it’s completely safe. I do it every day. Let me explain.
DNA stands for deoxyribonucleic acid. The words “acid” and “nucleic” are in the name so it is hardly surprising that some people are concerned about its effects when eaten.
But the name is nothing to worry about. While DNA is an acid, it’s a very weak one – more like vinegar, or the citric acid in lemons, than a dangerous acid like sulphuric acid.
What about the word “nucleic”? That has nothing to do with nuclear energy – it refers to the nucleus or centre of the living cell. The nucleus is the compartment where, in animals, plants and fungi, the DNA is stored. (In bacteria the DNA just floats around in the cell.)
The third part of the name – “deoxyribo” – also has a chemical sound to it but this just refers to ribose, which is a sugar a bit like glucose but with fewer carbons. The “deoxy” part means the ribose is missing one oxygen atom.
This makes DNA a very stable, non-reactive molecule and ideal for the long term storage of genetic information. It is also a good food.
Why am I so sure that eating DNA is safe?
I am sure because nearly all the food we eat contains DNA and lots of it. The reason is simple. Organisms are not built of continuous matter like plasticine, we are made up of tiny balloons called cells.
Ancient stories describe how people were fashioned from clay but actually it is more like being made of Lego blocks. Bacteria are single-celled organisms, most animals and plants are multi-celled organisms. Cats are bigger than mice because they have more cells.
In a sense, we are all like Lego constructions.
And here’s the amazing part – virtually every cell has its own DNA (its own genetic information or genome) and each cell in your body carries your genome. So each block is more like a smartphone than a balloon – each block has its own computer code or DNA genome.
In complex organisms each cell has the same DNA but interestingly different genes are active in different bodily organs. Think of genes as different apps on a smartphone – so all the smartphones that make up your liver will have one set of apps on, and your muscle cells will be using a different set of apps.
In plants, different apps (genes) are on in leaves and roots but all the cells of a plant carry the same set of genes, i.e. the same genome.
So whether you are a vegetarian who eats lettuce and cauliflower or an omnivore who eats steak and kidney pies, you are eating cells, and each cell contains DNA which in turn contains the entire genetic information or the whole genome of each species you eat.
The only living parts that don’t contain DNA are things like egg whites or filtered milk that are there for energy storage, or blood juices in which our blood cells float.
Carolina Biological Supply Company
DNA is pushed out of hair when it forms so hair doesn’t have much – if any – DNA, but hair roots do, and in mammals red blood cells (but not white blood cells) push out their DNA as they mature so they can squeeze along tiny blood vessels.
But most parts of animals and plants are made up of cells containing DNA. This is why police can identify suspects from either a drop of blood or a hair root at a crime scene. They could also identify a lettuce or a strawberry from a leaf or from the fruit.
If you eat a three course meal – oysters for starters, chicken and asparagus as a main, and fruit salad for dessert, you are eating lots of different DNA.
Can DNA from food get into my own DNA?
Basically, DNA, like proteins and complex carbohydrates, gets broken down into pieces – this is what digestion is all about. Your teeth mash it up and enzymes throughout your digestive tract cut it to pieces.
Enzymes produced by your pancreas called DNases are specially designed to break the DNA into tiny pieces that can be taken up into your blood and then carried around and used by other cells to build new molecular structures in your body – including possibly your own DNA.
Could any of the genes, from any of the organisms you eat, get into your DNA and do you harm? It’s a reasonable question, but the answer seems to be no. Imagine you dropped a smartphone in a blender or ate it (please don’t) – all the components would be mashed up.
When you eat and digest DNA it seems that the long coding sequences, the narratives or the apps that specify gene products, are so cut up that they can no longer function as genetic material. There are few if any sentences left, just letters or fragments of words.
Even if some sentences did survive your digestive system it is unlikely they would enter your cells or harm you in any way.
Our world is awash with DNA and always has been but there is no clear evidence that eating DNA can harm you.
Genetically modified organisms
So what about genetically modified organisms or GMOs? Are they safe to eat too?
I certainly think so. If you ate a fish with a gene from a strawberry or a strawberry with a gene from a fish, to me it is no different from eating fish for the main course and strawberries for dessert.
I don’t think eating DNA or any combination of different DNAs from different species could do us harm.
To convince yourself that DNA is contained in food you can do a simple experiment at home. You can extract DNA from fresh strawberries.
I wouldn’t eat the DNA alone though. When wet it is slimy and when dry it looks like cotton wool. But when mixed with the other components of strawberries it is undetectable and harmless, and strawberries taste great as they are.
Merlin Crossley works for the University of New South Wales. He receives funding from the Australian Research Council and the National Health and Medical Research Council.
Explainer: what is genomic editing?
Mistakes in the paper version of the Encyclopædia Britannica took a long time to correct – years often passed between revised editions – but these days editing information is much easier. In electronic sources, like Wikipedia, anyone can log on and use simple web-based tools to make corrections or even improvements.
Human genomes also contain various errors or mutations. Many are relatively harmless but some cause life threatening genetic diseases. In a few cases, patients have been treated by conventional gene therapy; new genes have been carried in by viruses. These can then compensate for defective genes. But so far few – if any – patients have had their mutations corrected by genomic editing.
Likewise in the agricultural world, most applications of genetic engineering have involved inserting new genes, termed transgenes, rather than using editing to incorporate desirable genetic variations.
Synchronous technological revolutions
This may all change now that new editing tools have come on the scene. A quiet revolution is occurring in our ability to modify living genomes.
John Jobby/Flickr, CC BY-SA
Most importantly the new editing tools have arrived in the midst of a second revolution – a revolution in our ability to sequence large genomes.
The affordable sequencing of human genomes has allowed the ready identification of myriad harmful mutations. Conversely, in agriculturally important organisms, new beneficial gene variants have been identified. So it is becoming more and more relevant to think about editing such variants in or out.
At the same time the improvements in sequencing also mean that one can readily re-sequence after editing. One can check whether any unintended errors have been introduced.
The big advantage of genomic editing over the addition of new genes by gene therapy or transgenesis is that a defect is corrected, or a desired variation is introduced, via a single, targeted and permanent change. Since the change already exists in nature, it should work effectively, and it should be safe.
In contrast, gene therapy has been severely hampered by the epigenetic silencing of transgenes, as well as by the unwanted insertion of new genes beside important growth control genes – that in one case led to uncontrolled cellular growth and cancer.
Tools for modifying genomes
So what are these new genomic editing tools, where did they come from, how do they work, and why are they not more widely talked about?
As often happens the new tools came from fundamental research – research into DNA-binding proteins or the mechanisms by which bacteria protect themselves from viruses. The key development is that it is now much easier to design DNA-targeting reagents that – at least in theory – can surgically cut a single gene within a complex genome.
Breaks in DNA can be lethal so the cell has in-built machinery that repairs any nick as soon as possible. One strategy is to grab any available spare DNA that seems to match the damaged DNA and to stitch it in as a replacement – just as you might darn a red pair of socks with any red wool that you find lying about in the cupboard. This is called homologous DNA repair.
Genomic editing is carried out by introducing a specific DNA-cutting module along with a piece of repair DNA, carrying the change you want to incorporate. When the original DNA gets cut, the cell replaces it with the donor DNA.
Surgically targetting chosen human genes
Bush 41 Library/Flickr, CC BY-NC-ND
The restriction enzyme EcoRI (that helps the bacterium E. coli protect itself from invading DNA viruses) recognises and cuts sequences of the form GAATTC (a string of DNA subunits or nucleotides and carrying in order a guanine, two adenines, two thymines and a cytosine). This sequence is only 6 units long and it occurs by chance millions of times in the human genome.
EcoRI is a useful tool when cutting and joining short pieces of DNA in the lab – pieces that only have one or two GAATTC motifs – but it is useless in terms of trying to surgically cut and repair a single human gene within our vast genome.
To get an idea of the importance of specificity, think of the Google search engine. If you typed in the word “editing” you might never find this article, but if you type in “genomic editing” you may. To be safe you could type in this whole sentence, or any other long sentence. The unique sequence of letters should be enough to take you right here.
A better toolbox
The first breakthrough in designing reagents that could target longer sequences came from the study of DNA-binding proteins in the model organism, the African clawed frog (Xenopus laevis).
Thomas Splettstoesser/Wikimedia Commons
His work showed that TFIIIA bound DNA via a series of short domains he called “zinc fingers” – because they curled around a zinc ion to form a shape that could stretch out to fit into the major groove of DNA.
He realised that each zinc finger could bind three nucleotides, and that by linking two zinc fingers together you could bind six. A protein of six zinc fingers can bind 18 base pairs, and so on. Like the long sentences mentioned above, 18-base pair sequences are sufficiently long to identify individual human genes.
These days many different artificial zinc fingers are available and can be linked together to target virtually any 18 base pair motif.
Artificial zinc finger proteins were then hooked up to DNA-cutting enzymes, or nucleases, to generate zinc finger nucleases. These have already proved effective in carrying out genomic editing – see the video below.
But they have also turned out to be more difficult than expected to make – the rational design approach did not always lead to the desired specificity in practice and a certain amount of trial and error and screening of random variants was required to achieve acceptable specificity and tightness of binding.
Consequently, a few companies, such as Sangamo Biosciences, offered a service in making zinc finger nucleases but few laboratories adopted the technology themselves.
Now things have really changed since two new DNA-binding modules have come on the scene:
1. Transcription activator-like effector nucleases (TALENs): these are based on DNA-binding proteins found naturally in bacteria that infect certain plants.
Like zinc finger proteins they are made up of repeated modules, and in this case each module binds to two bases. By linking nine domains together, scientists can make a protein that recognises 18 base pairs.
Most importantly the rules of binding have proved to be robust so that scientists can make modules to recognise any chosen doublet and these can then be stitched together. Many laboratories have eagerly adopted this technology to target their chosen genes.
2. Clustered regulatory interspaced short palindromic repeats (CRISPRs): these are similarly attractive.
Jawahar Swaminathan and MSD staff at the European Bioinformatics Institute, CC BY-NC-SA
They occur naturally in bacteria and, like restriction enzymes, are involved in protecting their hosts from viruses. But unlike ZFNs and TALENs, they use a guide ribonucleic acid (RNA) to find their target genes and they team up with a bacterial nuclease, Cas9, to execute the cutting.
This use of a guide RNA is important – RNA can base pair with DNA, using the well understood rules of base pairing.
It is now a simple matter to design CRISPRs against any desired sequence and many labs have swung into action and are doing just that.
So why isn’t this revolution being talked about?
The revolution has crept up on us because the breakthrough really revolves around better and cheaper tools rather than new ideas or concepts. Homologous recombination and genomic editing was already possible in simple organisms and it was feasible but expensive to make knock-out and knock-in mice. But it was slow and laborious. Now it is easier.
The other point concerns specificity. We know we can make the desired changes but we do not know how many other unintended changes are also being introduced.
In agriculture, if the sum of all changes results in the desired outcome, other unintended changes may not matter. But before anyone embarks on human genomic editing we will want to know about any off-target effects. With the availability of affordable genomic sequencing this should be possible and it is reasonable to be optimistic that refinements in specificity and nuclease delivery will, one day, make genomic editing a useful new therapeutic tool.
We will have to think carefully, however, before encouraging everyone to dive in to be a biological Wikipedia editor at home.
Merlin Crossley receives funding from the Australian Research Council and National Health and Medical Research Council.
The Science of Why We Don’t Believe Science
How our brains fool us on climate, creationism, and the vaccine-autism link.
—By Chris Mooney
| May/June 2011 Issue
“A MAN WITH A CONVICTION is a hard man to change. Tell him you disagree and he turns away. Show him facts or figures and he questions your sources. Appeal to logic and he fails to see your point.” So wrote the celebrated Stanford University psychologist Leon Festinger (PDF), in a passage that might have been referring to climate change denial—the persistent rejection, on the part of so many Americans today, of what we know about global warming and its human causes. But it was too early for that—this was the 1950s—and Festinger was actually describing a famous case study in psychology.
Festinger and several of his colleagues had infiltrated the Seekers, a small Chicago-area cult whose members thought they were communicating with aliens—including one, “Sananda,” who they believed was the astral incarnation of Jesus Christ. The group was led by Dorothy Martin, a Dianetics devotee who transcribed the interstellar messages through automatic writing.
Through her, the aliens had given the precise date of an Earth-rending cataclysm: December 21, 1954. Some of Martin’s followers quit their jobs and sold their property, expecting to be rescued by a flying saucer when the continent split asunder and a new sea swallowed much of the United States. The disciples even went so far as to remove brassieres and rip zippers out of their trousers—the metal, they believed, would pose a danger on the spacecraft.
Festinger and his team were with the cult when the prophecy failed. First, the “boys upstairs” (as the aliens were sometimes called) did not show up and rescue the Seekers. Then December 21 arrived without incident. It was the moment Festinger had been waiting for: How would people so emotionally invested in a belief system react, now that it had been soundly refuted?
At first, the group struggled for an explanation. But then rationalization set in. A new message arrived, announcing that they’d all been spared at the last minute. Festinger summarized the extraterrestrials’ new pronouncement: “The little group, sitting all night long, had spread so much light that God had saved the world from destruction.” Their willingness to believe in the prophecy had saved Earth from the prophecy!
From that day forward, the Seekers, previously shy of the press and indifferent toward evangelizing, began to proselytize. “Their sense of urgency was enormous,” wrote Festinger. The devastation of all they had believed had made them even more certain of their beliefs.
In the annals of denial, it doesn’t get much more extreme than the Seekers. They lost their jobs, the press mocked them, and there were efforts to keep them away from impressionable young minds. But while Martin’s space cult might lie at on the far end of the spectrum of human self-delusion, there’s plenty to go around. And since Festinger’s day, an array of new discoveries in psychology and neuroscience has further demonstrated how our preexisting beliefs, far more than any new facts, can skew our thoughts and even color what we consider our most dispassionate and logical conclusions. This tendency toward so-called “motivated reasoning” helps explain why we find groups so polarized over matters where the evidence is so unequivocal: climate change, vaccines, “death panels,” the birthplace and religion of the president (PDF), and much else. It would seem that expecting people to be convinced by the facts flies in the face of, you know, the facts.
The theory of motivated reasoning builds on a key insight of modern neuroscience (PDF): Reasoning is actually suffused with emotion (or what researchers often call “affect”). Not only are the two inseparable, but our positive or negative feelings about people, things, and ideas arise much more rapidly than our conscious thoughts, in a matter of milliseconds—fast enough to detect with an EEG device, but long before we’re aware of it. That shouldn’t be surprising: Evolution required us to react very quickly to stimuli in our environment. It’s a “basic human survival skill,” explains political scientist Arthur Lupia of the University of Michigan. We push threatening information away; we pull friendly information close. We apply fight-or-flight reflexes not only to predators, but to data itself.
We apply fight-or-flight reflexes not only to predators, but to data itself.
We’re not driven only by emotions, of course—we also reason, deliberate. But reasoning comes later, works slower—and even then, it doesn’t take place in an emotional vacuum. Rather, our quick-fire emotions can set us on a course of thinking that’s highly biased, especially on topics we care a great deal about.
Consider a person who has heard about a scientific discovery that deeply challenges her belief in divine creation—a new hominid, say, that confirms our evolutionary origins. What happens next, explains political scientist Charles Taber of Stony Brook University, is a subconscious negative response to the new information—and that response, in turn, guides the type of memories and associations formed in the conscious mind. “They retrieve thoughts that are consistent with their previous beliefs,” says Taber, “and that will lead them to build an argument and challenge what they’re hearing.”
In other words, when we think we’re reasoning, we may instead be rationalizing. Or to use an analogy offered by University of Virginia psychologist Jonathan Haidt: We may think we’re being scientists, but we’re actually being lawyers (PDF). Our “reasoning” is a means to a predetermined end—winning our “case”—and is shot through with biases. They include “confirmation bias,” in which we give greater heed to evidence and arguments that bolster our beliefs, and “disconfirmation bias,” in which we expend disproportionate energy trying to debunk or refute views and arguments that we find uncongenial.
That’s a lot of jargon, but we all understand these mechanisms when it comes to interpersonal relationships. If I don’t want to believe that my spouse is being unfaithful, or that my child is a bully, I can go to great lengths to explain away behavior that seems obvious to everybody else—everybody who isn’t too emotionally invested to accept it, anyway. That’s not to suggest that we aren’t also motivated to perceive the world accurately—we are. Or that we never change our minds—we do. It’s just that we have other important goals besides accuracy—including identity affirmation and protecting one’s sense of self—and often those make us highly resistant to changing our beliefs when the facts say we should.
American craft brewing just got a little stranger, and a little less animal-friendly. The brewsters at Philadelphia’s Dock Street Brewing Co. have announced the release of a new beer inspired by AMC’s zombie smash hit “The Walking Dead”: an American Pale Stout made with wheat, oats, flaked barley, organic cranberry and, of course, smoked goat brains. Yes, that’s right — smoked goat brains.
According to a press release, the line of thinking underpinning the brewery’s decision was, “Screw it, let’s use brains!”:
Gourmet mushrooms and potentially hallucinogenic herbs are one thing, but smoked brains… really? Believe it or not, much of the world considers brain to be a true delicacy. Think Indiana Jones and the Temple of Doom, but not ridiculous. Many also believe that using every part of an animal not only increases and encourages sustainability, but also honors the animal’s life and death.
Apparently, consuming an animal’s brain is also a way to honor one’s favorite television show. Dock Street Brewing Co. says their new brew is “quite possibly the smartest beer you’ll ever drink” — and we already know that goats are smarter than we’re wont to give them credit for being — but it’s unclear if there are benefits to adding the organ to beer.