Part 6 (1/2)

A more novel approach is the [email&160;protected] project, initiated by astronomers at the University of California at Berkeley in 1999 They hit upon the idea of enlisting millions of PC owners whose computers sit idle most of the tie that will help to decode sonals received by a radio telescope while the participant's screen saver is activated, so there is no inconvenience to the PC user So far the project has signed up 5over a billion dollars of electricity, all at little cost It is the most ambitious collective computer project ever undertaken in history and could serve as a model for other projects that need vast conal froent source has been found by [elaring lack of any progress in SETI research has forced its proponents to ask hard questions One obvious defect nals at certain frequency bands Sonals instead of radio signals Lasers have several advantages over radio, because a laser's short wavelength nals into one wave than you can with radio But because laser light is highly directional and also contains just one frequency, it is exceptionally hard to tune into precisely the right laser frequency

Another obvious defect ht be SETI researchers' reliance on certain radio frequency bands If there is alien life, it es via sies that are used on the es that have been spread over iven all the for SETI, it is reasonable to assume that sonal fro that such civilizations exist And should that happen, it would represent a milestone in the history of the human race

WHERE ARE THEY?

The fact that the SETI project so far has found no indication of signals froent life in the universe has forced scientists to take a cold, hard look at the assuent life on other planets Recently astronomical discoveries have led us to believe that the chance of finding intelligent life are inally coent life exists in the universe is both inally believed

First, new discoveries have led us to believe that life can flourish in ways not considered by Drake's equations Before, scientists believed that liquid water can exist only in the ”Goldilocks zone” surrounding the sun (The distance froht” Not too close to the sun, because the oceans would boil, and not too far away, because the oceans would freeze, but ”just right” to make life possible) So it came as a shock when astronomers found evidence that liquid water may exist beneath the ice cover on Europa, a frozen moon of Jupiter Europa is well outside the Goldilocks zone, so it would appear not to fit the conditions of Drake's equation Yet tidal forces ht be sufficient to melt the ice cover of Europa and produce a permanent liquid ocean As Europa spins around Jupiter, the planet's huge gravitational field squeezes thefriction deep within its core, which in turn could cause the ice cover to melt Since there are over one hundred moons in our solar system alone, thismoons in our solar systeiant extrasolar planets so far discovered in space ht also have frozen moons that can support life) Furthermore, scientists believe the universe could be peppered andering planets that no longer circle around any star Because of tidal forces, any ht have liquid oceans under its ice cover and hence life, but such moons would be i light from the reatly outnuiven that there could be alaxy, the number of astronoht be er than previously believed

On the other hand, other astronomers have concluded, for a variety of reasons, that the chances for life on planets within the Goldilocks zone are probably inally estirams show that the presence of a Jupiter-sized planet in a solar syste co out a solar syste life possible If Jupiter did not exist in our solar syste life iie Institution in Washi+ngton, DC, estimates that without the presence of Jupiter or Saturn in our solar system, the Earth would have suffered a thousand ti impact (like the one that destroyed the dinosaurs 65every ten thousand years ”It's hard to iht,” he says

Second, our planet is blessed with a largeNewton's laws of gravity over e moon, our Earth's axis probably would have beco life impossible French astronomer Dr Jacques Lasker estimates that without our rees, which would precipitate extreme weather conditions incoe moon also has to be factored into conditions used for Drake's equations (The fact that Mars has two tiny moons, too small to stabilize its spin, means that Mars ain in the future) Third, recent geological evidence points to the fact that uished About 2 billion years ago the Earth was probably completely covered in ice; it was a ”sobll Earth” that could barely support life At other tiht have co all life on Earth So the creation and evolution of life is ht

Fourth, intelligent life was also nearly extinguished in the past About a hundred thousand years ago there were probably only a few hundred to a few thousand humans, based on the latest DNA evidence Unlike iven species, which are separated by large genetic differences, huenetically Codom, we are almost like clones of each other This phenomenon can only be explained if there were ”bottlenecks” in our history in which most of the hue volcanic eruption et cold, nearly killing off the entire human race

There are still other fortuitous accidents that were necessary to spawn life on Earth, includingA strong netic field This is necessary in order to deflect cosmic rays and radiation that could destroy life on Earth

A moderate speed of planetary rotation If the Earth rotated too slowly, the side facing the sun would be blisteringly hot, while the other side would be freezing cold for long periods of time; if the Earth rotated too quickly, there would be extremely violent weather conditions, such as ht distance froalaxy If the Earth were too close to the center of the Milky Way galaxy, it would be hit with dangerous radiation; if it were too far froher elements to create DNA molecules and proteins

For all these reasons astronoht exist outside the Goldilocks zone onplanets, but that the chances of the existence of a planet like Earth capable of supporting life within the Goldilocks zone are much lower than previously believed Overall most esti civilization in the galaxy are probably sinally estimated

As Professors Peter Ward and Donald Brownlee have written, ”We believe that life in the form of microbes and their equivalents is very common in the universe, perhaps an envisioned However, coher plants-is likely to be far more rare than is commonly assumed” In fact, Ward and Brownlee leave open the possibility that the Earthanih this theory alaxy, it still leaves open the possibility of life existing in other distant galaxies) THE SEARCH FOR EARTH-LIKE PLANETS

Drake's equation, of course, is purely hypothetical That is why the search for life in outer space has gotten a boost from the discovery of extrasolar planets What has hindered research into extrasolar planets is that they are invisible to any telescope since they give off no light of their own They are in general a million to a billion times dimmer than the mother star

To find thes in the e Jupiter-sized planet is capable of altering the orbit of the star (I its tail In the same way, the mother star and its Jupiter-size planet ”chase” each other by revolving around each other A telescope cannot see the Jupiter-sized planet, which is dark, but the mother star is clearly visible and appears to wobble back and forth) The first true extrasolar planet was found in 1994 by Dr Alexandr Wolszczan of Pennsylvania State University, who observed planets revolving around a dead star, a rotating pulsar Because the mother star had probably exploded as a supernova, it seemed likely that these planets were dead, scorched planets The following year tiss astronomers, Michel Mayor and Didier Queloz of Geneva, announced that they had found aplanet with a asi Soon after that the floodgates were opened

In the last ten years there has been a spectacular acceleration in the nuist Bruce Jakosky of the University of Colorado at Boulder says, ”This is a special tieneration that has a realistic chance of discovering life on another planet”

None of the solar systems found so far resemble our own In fact, they are all quite dissiht that our solar systehout the universe, with circular orbits and three rings of planets surrounding the mother star: a rocky belt of planets closest to the star, next a belt of gas giants, and finally a cos

Much to their surprise, astronomers found that none of the planets in other solar systems followed that simple rule In particular, Jupiter-sized planets were expected to be found far from the mother star, but instead many of them orbited either extremely close to the mother star (even closer than the orbit of Mercury) or in extremely elliptical orbits Either way the existence of a s in the Goldilocks zone would be impossible in either condition If the Jupiter-sized planet orbited too close to the rated froradually spiraled into the center of the solar system (probably due to friction caused by dust) In that case, the Jupiter-size planet would eventually cross the orbit of the s it into outer space And if the Jupiter-sized planet followed a highly elliptical orbit, it would ularly through the Goldilocks zone, again causing any Earth-like planet to be flung into space

These findings were disappointing to planet hunters and astrono to discover other Earth-like planets, but in hindsight these findings were to be expected Our instruest, fastest- Jupiter-sized planet that can have a measurable effect on thethat today's telescopes can detect onlyrapidly in space If an exact twin of our own solar system exists in outer space, our instruments are probably too crude to find it

All thisof Corot, Kepler, and the Terrestrial Planet Finder, three satellites that are designed to locate several hundred Earth-like planets in space The Corot and Kepler satellites, for example, will examine the faint shadow that would be cast by an Earth-like planet as it crosses the face of the h the Earth-like planet would not be visible, the reduction in sunlight from the mother star could be detected by satellite

The French Corot satellite (which in French stands for Convection, Stellar Rotation, and Planetary Transits) was successfully launched on December 2006 and represents a milestone, the first space-based probe to search for extrasolar planets Scientists hope to find between ten and forty Earth-like planets If they do, the planets will probably be rocky, not gas giants, and will be just a few tier than the Earth Corot will also probably add to the many Jupiter-sized planets already found in space ”Corot will be able to find extrasolar planets of all sizes and natures, contrary to e can do froround at the ether scientists hope the satellite will scan up to 120,000 stars

Any day, the Corot may find evidence of the first Earth-like planet in space, which will be a turning point in the history of astrono at the night sky and realizing that there are planets out there that could harbor intelligent life When we look into the heavens in the future, weback

The Kepler satellite is tentatively scheduled for launch in late 2008 by NASA It is so sensitive that it may be able to detect up to hundreds of Earth-like planets in outer space It will htness of 100,000 stars to detect the motion of any planet as it crosses the face of the star During the four years it will be in operation, Kepler will analyze and ht-years from Earth In its first year in orbit, scientists expect the satellite to find roughly50 planets about the saer than the Earth, and640 planets about 22 times the size of the Earth

The Terrestrial Planet FinderEarth-like planets After several delays, it is tentatively scheduled for launch in 2014; it will analyze as reat accuracy It will be equipped with two separate devices to search for distant planets The first is a coronagraph, a special telescope that blocks out the sunlight froht by a factor of a billion The telescope will be three to four tier than the Hubble space Telescope and ten times more precise The second device on the Finder is an interferoht waves to cancel the light from the mother star by a factor of a ency is planning to launch its own planet finder, the Darwin, to be sent into orbit in 2015 or later It is planned to consist of three space telescopes, each about 3 e interferometer Its mission, too, will be to identify Earth-like planets in space

Identifying hundreds of Earth-like planets in outer space will help to refocus the SETI effort Instead of rando nearby stars, astronomers will be able to pinpoint their efforts on a small collection of stars that may harbor a twin of the Earth

WHAT DO THEY LOOK LIKE?

Other scientists have tried to use physics, biology, and cheht look like Isaac Newton, for example, wondered why all the animals he could see around him possessed the saed symmetrically Was this a fortuitous accident or an act of God?

Today biologists believe that during the ”Cao, nature experiing multicellular creatures Some had spinal cords shaped like an X, Y, or Z Some had radial symmetry like a starfish By accident one had a spinal cord shaped like an I, with bilateral symmetry, and it was the ancestor of most mammals on Earth So in principle the humanoid shape with bilateral symmetry, the same shape that Hollywood uses to depict aliens in space, does not necessarily have to apply to all intelligent life

Soists believe that the reason that diverse life-for the Cambrian explosion is because of an ”arence of the first anisms forced an accelerated evolution of the tith each one racing to outmaneuver the other Like the arms race between the for the cold war, each side had to hustle to keep ahead of the other

By exa how life evolved on this planet, one ent life ht have evolved on Earth Scientists have concluded that intelligent life probably requires 1 So mechanisrabbing-it could also be a tentacle or claw; 3 Some sort of communication system, such as speech

These three characteristics are required for sensing our environ it-both of which are the hallence But beyond these three characteristics, anything goes Contrary to so many of the aliens shown on TV, an extraterrestrial does not have to rese-eyed aliens we see on TV and in the movies, in fact, look suspiciously like the 1950s aliens frorade movies, which are firists, however, have added a fourth criteria for intelligent life to explain a curious fact: huent than they have to be to survive in the forest Our brains can master space travel, the quantum theory, and advanced mathe and scavenging in the forest Why this excess brainpower? In nature e see pairs of animals like the cheetah and the antelope that possess extraordinary skills far beyond those required for survival, we find that there was an arms race between them Similarly, soical ”arent humans Perhaps that arms race ith other members of our own species) Think of all the remarkably diverse life-forms on the Earth If one, for example, could selectively breed octopods for several ht also becoo, probably because ere not well adapted to the changing environment of Africa By contrast, the octopus is very well adapted to its life beneath a rock and hence has not evolved for millions of years) Biocheazes at all the ”crazy-looking crustaceans, squishy-tentacled jellyfish, grotesque, hermaphroditic worms, and slime molds, I know that God has a sense of humor, and ill see this reflected in other forets it right when it depicts intelligent alien life-forger box office sales, there is also an element of truth to the depiction Predators are usually s to plan, stalk, hide, and aers, and lions have eyes that are on the front of their face in order to judge distance when they pounce on their prey With two eyes, they can use 3-D stereo-vision to lock on to their prey Prey, such as deer and rabbits, on the other hand, just have to kno to run They have eyes that are on the side of their face in order to scan for predators 360 degrees around theent life in outer spaceorgan, on the front of their face They ressive, and territorial behavior we find in wolves, lions, and humans on Earth (But since such life-forms would probably be based on entirely different DNA and proteinwith, us) We can also use physics to conjecture what their body sizethey live on Earth-sized planets and have the sae creatures are probably not possible because of the scale lahich states that the laws of physics change drastically as we increase the scale of any object

MONSTERS AND THE SCALE LAW

If King Kong really existed, for example, he would not be able to terrorize New York City On the contrary, his legs would break as soon as he took a single step This is because if you take an ape and increase his size by 10 tio up by the increased volume, or by 10 10 10 = 1,000 tith increases relative to the thickness of his bones and oes up by only a square of the distance, that is, by 10 10 = 100 tier, he would be only 100 tih 1,000 tiht increases th as we increase its size He would be, relatively speaking, 10 tis would break

In eleth of an ant, which can lift a leaf ht My teacher concluded that if an ant were the size of a house, it could pick up that house But this assumption is incorrect for the sa If an ant were the size of a house, its legs would also break If you scale up an ant by a factor of 1,000, then it would be 1,000 times weaker than a norht (It would also suffocate An ant breathes through holes in the sides of its body The area of these holes grows as per the square of the radius, but the volume of the ant increases as per the cube of the radius Thus an ant 1,000 tier than an ordinary ant would have 1,000 tien for its muscles and body tissue This is also the reason that chayh they have the sareater proportionatethe scale lae can also calculate the rough shape of animals on Earth, and possibly aliens in space The heat emitted by an ani its size by 10 increases its heat loss by 10 10 = 100 But the heat content within its body is proportional to its volue animals lose heat more slowly than sers and ears freeze first, since they have the et colder faster than large people It explains why newspapers burn very quickly, because of their large relative surface area, while logs burn very slowly, because of their relatively small surface area) It also explains hales in the Arctic are round in shape-because a sphere has the smallest possible surface area per unit mass And why insects in a warmer environe surface area per unit mass

In the Disney movie Honey, I Shrunk the Kids a family is shrunk down to the size of ants A rainstorm develops, and in theonto puddles In reality a raindrop as seen by an ant would appear not as a tiny drop but as a huge mound or hemisphere of water In our world a hemispherical ht under gravity But in the e, so a hemispherical mound of water is perfectly stable

Sih surface-to-volu the laws of physics Using these lae can theorize that aliens in outer space would likely not be the giants often portrayed in science fiction, but would more closely reseer in size because of the buoyancy of seawater This also explains why a beached whale dies-because it is crushed by its oeight) The scale law o deeper and deeper into the microworld This explains why the quantu simple commonsense notions about our universe So the scale law rules out the familiar idea of worlds-within-worlds found in science fiction, that is, the idea that inside the atoalaxy could be an atoer universe This idea was explored in the movie Men in Black In the final scene of the movie the camera pans away froalaxies, until our entire universe becoaalaxy of stars bears no resemblance to an atom; inside the atom the electrons inside their shells are totally different from planets We know that all the planets are quite different from each other and can orbit at any distance from the mother star In atoms, however, all the subatomic particles are identical to one another They cannot orbit at any distance from the nucleus, but only in discrete orbits (Furthermore, unlike planets, electrons can exhibit bizarre behavior that violates co two places at the sa wavelike properties) THE PHYSICS OF ADVANCED CIVILIZATIONS

It is also possible to use physics to sketch out the outlines of possible civilizations in space If we look at the rise of our own civilization over the past 100,000 years, since ed in Africa, it can be seen as the story of rising energy consumption Russian astrophysicist Nikolai Kardashev has conjectured that the stages in the development of extraterrestrial civilizations in the universe could also be ranked by energy consurouped the possible civilizations into three types: 1 Type I civilizations: those that harvest planetary power, utilizing all the sunlight that strikes their planet They can, perhaps, harness the power of volcanoes, manipulate the weather, control earthquakes, and build cities on the ocean All planetary power is within their control

2 Type II civilizations: those that can utilize the entire power of their sun,them 10 billion times more powerful than a Type I civilization The Federation of Planets in Star Trek is a Type II civilization A Type II civilization, in a sense, is ies, meteor impacts, or even supernovae, can destroy it (In case their s can move to another star system, or perhaps even move their home planet) 3 Type III civilizations: those that can utilize the power of an entire galaxy They are 10 billion ti in Star Trek, the Ealactic civilization in Asimov's Foundation series correspond to a Type III civilization They have colonized billions of star systems and can exploit the power of the black hole at the center of their galaxy They freely roaalaxy

Kardashev esti at a y consuress rapidly from one type to the next, within a matter of a few thousand years to tens of thousands of years

As I've discussed in my previous books, our own civilization qualifies a Type 0 civilization (ie, we use dead plants, oil and coal, to fuel our y that falls on our planet But already we can see the beginnings of a Type I civilization e of a Type I telephone syste of a Type I economy can be seen in the rise of the European Union, which in turn was created to colish is already the nue of science, finance, and business I ie spoken by virtually everyone Local cultures and customs will continue to thrive in thousands of varieties on the Earth, but superimposed on this mosaic of peoples will be a planetary culture, perhaps dominated by youth culture and commercialism

The transition between one civilization and the next is far froerous transition, for example, may be between a Type 0 and a Type I civilization A Type 0 civilization is still wracked with the sectarianism, fundamentalism, and racism that typified its rise, and it is not clear whether or not these tribal and religious passions will overwhelm the transition (Perhaps one reason that we don't see Type I civilizations in the galaxy is because they never made the transition, ie, they self-destructed One day, as we visit other star systems, we may find the remains of civilizations that killed the, their atmospheres became radioactive or too hot to sustain life) By the tiy and kno to travel freely throughout the galaxy and even reach the planet Earth As in the , robotic probes throughout the galaxy searching for intelligent life