How Did We Get Here?

Astronomers cannot see all the way back in time to the origin of the universe, but by drawing on lots of clues and theory, they can imagine how everything began. 

Their model starts with the entire universe as a very hot dot, much smaller than the diameter of an atom. The dot began to expand faster than the speed of light, an expansion called the Big Bang. Cosmologists are still arguing about the exact mechanism that may have set this event in motion. From there on out, however, they are in remarkable agreement about what happened. As the baby universe expanded, it cooled the various forms of matter and antimatter it contained, such as quarks and leptons, along with their antimatter twins, antiquarks and antileptons. These particles promptly smashed into and annihilated one another, leaving behind a small residue of matter and a lot of energy. The universe continued to cool down until the few quarks that survived could latch together into protons and neutrons, which in turn formed the nuclei of hydrogen, helium, deuterium, and lithium. For 300,000 years, this soup stayed too hot for electrons to bind to the nuclei and form complete atoms. But once temperatures dropped enough, the same hydrogen, helium, deuterium, and lithium atoms that are around today formed, ready to start a long journey into becoming dust, planets, stars, galaxies, and lawyers. 

Gravity—the weakest of the forces but the only one that acts cumulatively across long distances—gradually took control, gathering gas and dust into massive globs that collapsed in on themselves until fusion reactions were ignited and the first stars were born. At much larger scales, gravity pulled together huge regions of denser-than-average gas. These evolved into clusters of galaxies, each one brimming with billions of stars. 

Over the eons fusion reactions inside stars transformed hydrogen and helium into other atomic nuclei, including carbon, the basis for all life on Earth. 

The most massive stars sometimes exploded in energetic supernovas that produced even heavier elements, up to and including iron. Where the heaviest elements, such as uranium and lead, came from still remains something of a mystery. 

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Flawed Gravity, or Relaxing the Grip

For almost a century, Albert Einstein’s Theory of General Relativity has reigned as the explanation for how gravity works. Einstein’s equations showed that gravity is a property of matter, and that matter "warps" the space-time around it.

Yet there are both problems with General Relativity and questions about its effects.

"Perhaps we see the acceleration of the universe and we attribute that to energy, but maybe our theory of gravity is still incomplete, so we don’t need extra energy, we just need to modify our theory."
Eiichiro Komatsu,
University of Texas at Austin

Relativity applies to the universe on large scales, but not on the smallest scales, where quantum gravity takes over. Relativity also breaks down in the presence of the strongest gravitational fields, like those at the center of a black hole.

All the experiments to date have confirmed General Relativity’s effects on large scales, but scientists still aren’t certain whether gravity has remained constant since the Big Bang, whether it acts the same in all regions of the universe, and whether it retains its grip on the very largest scales.

It’s possible that gravity weakens on the largest scales – across billions of light-years – and thereby allowing the universe to expand at a faster rate as it grows larger.

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New Physics, or Particles and Fields

Scientists have discovered a menagerie of particles, and suspect that the universe contains many more — perhaps including particles of dark energy and dark matter. 

Physicists have observed lots of particles in the universe: the protons, neutrons, and electrons that make up atoms; the quarks that make up protons and neutrons; and particles with such exotic names as muons, leptons, and neutrinos. At the same time, they have observed many "fields" that play important roles in the universe: magnetic fields, electric fields, and gravitational fields, among others.

And they are looking for even more. The world’s largest particle accelerator, which is scheduled to begin operations in Europe in 2008, will search for a particle called the Higgs boson, which may be responsible for the "field" that gives mass to some particles but not others. In fact, particles and fields are just different descriptions of the same phenomena. Just as matter and energy are equivalent, as Albert Einstein described in his theories of relativity, particles and fields are equivalent, too.

The search for new particles and fields extends to the search for dark energy and dark matter.

Dark matter fills the universe, and exerts a gravitational pull on the "normal" matter, like stars and planets, around it. Yet it produces no detectable form of energy – no light, heat, radio waves, or anything else. Some physicists believe that dark matter is a form of particle that was produced in the Big Bang but that has not yet been detected.

Dark energy may consist of an undiscovered energy field that permeates the universe, and that may change over time.

Dark energy, of course, is still in the early stages of study. Physicists who feel that vacuum energy has too many problems are looking for other solutions, and one contender is a new type of particle. Dark-energy particles likely would have been created in the Big Bang as well, and would permeate the entire universe.

Others describe a new field that permeates the universe, called quintessence. One key difference from the vacuum energy is that quintessence would vary with time, so it might not show up at all in the early universe, but exert a powerful influence today. There are several hypotheses of quintessence fields, and in each one, each with a different outcome for the future of the universe.

So far, there’s no evidence of dark energy particles or fields. Discovering them would require not only the efforts of astronomers, but new experiments for even more powerful particle accelerators, which are decades away.

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Vacuum Energy, or Einstein’s Blunder

1. Empty space. 2. Two particles suddenly appear. 3. Particles ram together and annihilate each other. 4. They leave ripples of energy through space.

If Las Vegas were taking bets on dark energy, the odds would favor a concept known as vacuum energy or the cosmological constant. In essence, it suggests that space itself produces energy, which is "pushing" the universe outward.

Albert Einstein invented the cosmological constant as part of his theory of gravity, known as General Relativity.


1. Empty space. 2. Two particles suddenly appear. 3. Particles ram together and annihilate each other. 4. They leave ripples of energy through space. [Tim Jones]
Einstein’s equations showed that the gravity of all the matter in the universe would exert a strong pull, pulling all the stars and galaxies toward each other and eventually causing the universe to collapse. At the time, though, astronomers believed that the universe was static – that it was neither expanding nor contracting. To counteract this problem, Einstein added another term to his equations, called the cosmological constant, to balance the inward pull of gravity.

Within about a decade, though, astronomer Edwin Hubble discovered that the universe is expanding. Einstein discarded the cosmological constant, calling it his greatest scientific blunder.

When dark energy was discovered, though, many physicists began to think that Einstein’s only blunder was in removing the constant. This "repulsive" force could begin to explain the acceleration of the universe. In other words, it might be the dark energy.

Today, physicists explain the cosmological constant as the vacuum energy of space.

In essence, this says that pairs of particles are constantly popping into existence throughout the universe. These "virtual pairs" consist of one particle with a negative charge and one with a positive charge. They exist for only a tiny fraction of a second before they collide and annihilate each other in a tiny burst of energy. This energy may be pushing outward on space itself, causing the universe to accelerate faster.

One of the appealing elements of vacuum energy is that it could explain why the acceleration has only started fairly recently on the cosmic timescale.

In the early universe, all the matter was packed much more densely today. In other words, there was less space between galaxies. With everything so close together, gravity was the dominant force, slowing down the acceleration of the universe that was imparted in the Big Bang. In addition, since there was less space in the universe, and the vacuum energy comes from space itself, it played a much smaller role in the early universe.

Today – 13.7 billion years after the Big Bang – the universe has grown much larger, so the galaxies are not packed so close together. Their gravitational pull on each other is weakened, allowing the vacuum energy to play a more dominant role.

Vacuum energy has its own set of problems, though. It should be far too weak to account for the acceleration seen in the present-day universe, for example — by a factor of at least 1057 (a one followed by 57 zeroes), and perhaps as much as 10120 (a one followed by 120 zeroes). Yet it is the most complete scenario to date, so it leads the pack of dark-energy contenders.

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What is dark energy?

Like the "dark side of the Moon," dark energy represents the unknown. In the late 1990s, astronomers discovered that the universe is expanding faster today than they had expected. But they don’t know what is causing the acceleration, so for now, they simply call it "dark energy."

"Dark energy is our ignorance of what’s going on in the universe right now," says Karl Gebhardt, a professor of astronomy at The University of Texas at Austin and one of the principal investigators for the Hetdex project

"What I always like to say is that dark energy is only a phrase, and don’t get hung up on the words dark and energy. [Dark energy] may not be dark, and it may not be energy. All it is is our ignorance of how the universe may be expanding, and we don’t know what it is at this point."

Even so, theorists have already developed several explanations for dark energy. These explanations include an energy born from space itself, new kinds of subatomic particles, and even a flaw in the theory of gravity. Hetdex and later experiments will allow physicists to select the correct one.

"Whatever the answer is," says Gebhardt, "it’s going to be a fundamental change in our understanding of the basic properties of the universe."

Vacuum Energy, or Einstein’s Blunder

If Las Vegas were taking bets on dark energy, the odds would favor a concept known as vacuum energy or the cosmological constant. In essence, it suggests that space itself produces energy, which is "pushing" the universe outward.

New Physics, or Particle X

Physicists have observed lots of particles in the universe: the protons, neutrons, and electrons that make up atoms; the quarks that make up protons and neutrons; and particles with such exotic names as muons, leptons, and neutrinos.

Flawed Gravity, or Relaxing the Grip

For almost a century, Albert Einstein’s Theory of General Relativity has reigned as the explanation for how gravity works. Einstein’s equations showed that gravity is a property of matter, and that matter "warps" the space-time around it.

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Father of modern Astronomy

Father of Astronomy :- Galileo Galilei

Galileo Galilei

Galileo Galilei, was an Italian physicist, mathematician, astronomer, and philosopher who played a major role in the Scientific Revolution.

Galileo, known by his first name only, was an astronomer, inventor, Physicist and mathematician. He was born February 15, 1564 in Pisa, to a father, who was a famous lutanist ( lute is a stringed instrument with a pear shaped body ) .

His father, Vincenzo Galilei, wrote several books on music history and theory, one of which analyzed both old and modern music entitled "Dialogo della musica antica e moderna" ( Dialog of old and modern music ) which was published in 1581. Vincenzo Galilei was also experimenter by nature, and combined the practice and the theory of music. He was the first to discover the ratio of string lengths to octaves. It had been believed that the ratio was 2:1, but he proved that it was 4:1 by his experiments that hung weights from strings. Galileo was raised by a father who used mathematics and experimentation in his musical studies. Similarly, Galileo, in his own life, also used mathematics and experimentation to rock the foundations of the world scientific, philosophical and religious establishments.

Galileo entered Pisa University as a medical student in 1581. He later decided to become a mathematician and from1592 to 1610 was professor of mathematics at Padua University. Galileo taught himself optics and ingeniously used the lenses available at the time to build a telescope with significant magnification. His passion to study the heavens drove him to experiment with optics, and ultimately, invent the modern telescope.

 In 1609, his first had a magnification power of 30, which was a massive power for his day. Other very crude spyglasses existed at the time with double or triple magnification and were used by ships captains or military leaders. There are two known examples of magnification spyglasses long before Galileo’s powerful telescope. For example, Leonardo da Vinci studied optics and designed a telescope 100 years before Galileo, but the optics of his day prevented da Vinci from building one with much magnification. His designs and analysis included curved mirrors and glass hemispheres. Da Vinci even developed a means of testing mirrored surfaces for quality anticipating the Hartman optical method. The famous Arab scientist Alhazen documented an even earlier writing of a primitive magnifying lens around 1000 AD. The Roman emperor Nero (37AD-67AD) used an emerald as a means of magnifying the view of events in a large arena. Also, Hans Lipperhey in Holland patented a primitive telescope in 1608, but it was based upon early models.
Nevertheless, Galileo built the first modern telescope and was the first to build one powerful enough to study the heavens. Perhaps more importantly, Galileo used his new telescope to make new scientific discoveries that greatly enlightened the world.

Using his new invention, Galileo systematically studied the sky. He made many fantastic astronomical discoveries and today he is considered the father of Modern Astronomy. Galileo was the first to provide evidence that confirmed the theory of the great Polish astronomer Nicolaus Copernicus that the Sun, not the earth, was at the center of the solar system. Galileo’s studies of the crescent phase of Venus provided the first evidence that the hearth was not at the center of the solar system and that the earth moved around the sun.

Galileo was the first to discover that Jupiter had a group of moons and noted that the ones closer to 

Jupiter moved faster than the ones further away. He also was the first to discover that the earth’s moon has craters. He also discovered that the Sun was spotted with dark areas and he was the first to think these Sunspots were related to the nature of the sun itself.

In 1989, the U.S. space agency NASA launched the Galileo spacecraft, named in Galileo’s honor, to explore Jupiter and his moons. It reached Jupiter on December 7^th1995. The spacecraft’s mission was highly successful and brought back amount of information on Jupiter and his moons, Venus, and asteroid belts.

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Who Invented the Rocket?

Although the Chinese are credited with having invented the rocket as early as the 3rd Century AD, it was not until the 20th Century that it began to take on its modern form. For that, we can thank a Russian mathematician, an American professor, and an Austro-Hungarian physicist.

Who Invented the Rocket? Konstantin Tsiolkovsky, Robert Goddard, Hermann Oberth

In 1903, Konstantin Tsiolkovsky published a seminal work, The Exploration of Cosmic Space by Means of Reaction Devices. In the volume, he calculated the speed required to send an object into a minimal orbit around the Earth. He also described how this feat could be achieved using a multi-stage rocket fueled with liquid oxygen and liquid hydrogen.

Tsiolkovsky worked out many of the details associated with rocketry and space travel. He conceived of fuel pump systems, space stations, rockets with steering thrusters, airlocks for spacewalks, optimal trajectories for returning spacecraft, and close-loop life support systems.

However, Tsiolkovsky was a theorist who was ahead of his time. The practical work of putting his theories into practice was done by others. One of them was an American professor named Robert Goddard, who proved adept at both the theoretical and practical sides of rocketry.

Goddard invented the first modern rocket. On the cold day of March 16, 1926, Goddard launched a liquid-fueled rocket for the first time in Auburn, Massachusetts. The rocket, which he named Nell, rose to an altitude of 41 feet in 2.5 seconds before crashing into a cabbage field.

Over the 15 years that followed, Goddard and his team launched a total of 34 rockets, reaching speeds of 550 miles per hour and altitudes of 1.6 miles. Goddard also developed three-axis control, gyroscopes, and steerable thrust systems to control rockets in flight. He secured 214 patents, including designs for multi-stage and liquid-fuel rockets. In 1919, Goddard published a book, A Method of Reaching Extreme Altitudes, which became a classic text in rocketry.

Stung by the press for criticism of his pioneering work, Goddard became very private in his later years. Thus, he didn’t get nearly as much credit for his achievements during his lifetime. Only years after he died in 1945 was Goddard recognized as one of the fathers of modern rocketry.

During the same period that Goddard was launching his rockets, an Austro-Hungarian physicist named Hermann Oberth was becoming a well-known rocket expert in Europe. In 1923, he published an influential book, By Rocket into Interplanetary Space, laying out how rockets could fly in space. Six years later, he expanded upon that text with a sequel, Ways to Spaceflight.

In 1928, a copy of By Rocket into Interplanetary Space found its way into the hands of a 16-year-old Prussian aristocrat named Wernher von Braun. The young student had always been interested in space, and here was a practical guide on how to get there.

Oberth would become a mentor to von Braun. Both became active members in the Society for Space Travel, an amateur group that conducted rocket launches outside of Berlin in the early 1930s. The society later folded, and von Braun would go on to lead the German Army rocket team that launched the first ballistic missile, the V-2, in 1942. By that time, Oberth was working for von Braun, his former student.

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A Brief History of Animals in Space

Before humans actually went into space, one of the prevailing theories of the perils of space flight was that humans might not be able to survive long periods of weightlessness. For several years, there had been a serious debate among scientists about the effects of prolonged weightlessness. American and Russian scientists utilized animals - mainly monkeys, chimps and dogs - in order to test each country's ability to launch a living organism into space and bring it back alive and unharmed.

Albert

On June 11, 1948, a V-2 Blossom launched into space from White Sands, New Mexico carrying Albert I, a rhesus monkey. Lack of fanfare and documentation made Albert an unsung hero of animal astronauts. On June 14, 1949, a second V-2 flight carrying a live Air Force Aeromedical Laboratory monkey, Albert II, attained an altitude of 83 miles. The monkey died on impact. On August 31, 1948, another V-2 was launched and carried an unanaesthetized mouse that was photographed in flight and survived impact. On December 12, 1949, the last V-2 monkey flight was launched at White Sands. Albert IV, a rhesus monkey attached to monitoring instruments, was the payload. It was a successful flight, with no ill effects on the monkey until impact, when it died. In May 1950, the last of the five Aeromedical Laboratory V-2 launches (known as the Albert Series) carried a mouse that was photographed in flight and survived impact.

On September 20, 1951, a monkey named Yorick and 11 mice were recovered after an Aerobee missile flight of 236,000 feet at Holloman Air Force Base, New Mexico. Yorick got a fair amount of press as the first monkey to live through a space flight.

On May 22, 1952, two Philippine monkeys, Patricia and Mike, were enclosed in an Aerobee nose section at Holloman Air Force Base. Patricia was placed in a seated position and Mike in a prone position to determine differences in the effects of rapid acceleration. Fired 36 miles up at a speed of 2000 mph, these two monkeys were the first primates to reach such a high altitude. Also on this flight were two white mice, Mildred and Albert. They were inside a slowly rotating drum where they could "float" during the period of weightlessness. The section containing the animals was recovered safely from the upper atmosphere by parachute. Patricia died of natural causes about two years later and Mike died in 1967, both at the National Zoological Park in Washington, DC.

The Soviets kept close tabs on what the U.S. was doing with their V-2 and Aerobee missile projects during the early 1950's. Basing their experiments on American biomedical research, Soviet rocket pioneer Sergei Korolev, his biomedical expert Vladimir Yazdovsky, and a small team used mice, rats and rabbits as one-way passengers for their initial tests. They needed to gather data to design a cabin to carry a human being into space. Eventually they chose small dogs for this phase of testing. Dogs were chosen over monkeys because it was felt that they would be less fidgety in flight. A test with two dogs would allow for more accurate results. They chose females because of the relative ease of controlling waste.

Between 1951 and 1952, the Soviet R-1 series rockets carried nine dogs altogether, with three dogs flying twice. Each flight carried a pair of dogs in hermetically sealed containers that were recovered by parachute. Of these early space-bound hounds, a few have been remembered by name.

On August 15, 1951, Dezik and Tsygan ("Gypsy") were launched. These two were the first canine suborbital astronauts. They were successfully retrieved. In early September 1951, Dezik and Lisa were launched. This second early Russian dog flight was unsuccessful. The dogs died but a data recorder survived. Korolev was devastated by the loss of these dogs. Shortly afterwards, Smelaya ("Bold") and Malyshka ("Little One") were launched. Smelaya ran off the day before the launch. The crew was worried that wolves that lived nearby would eat her. She returned a day later and the test flight resumed successfully. The fourth test launch was a failure, with two dog fatalities. However, in the same month, the fifth test launch of two dogs was successful. On September 15, 1951, the sixth of the two-dog launches occurred. One of the two dogs, Bobik, escaped and a replacement was found near the local canteen. She was a mutt, given the name ZIB, the Russian acronym for "Substitute for Missing Dog Bobik." The two dogs reached 100 kilometers and returned successfully. Other dogs associated with this series of flights included Albina ("Whitey"), Dymka ("Smoky"), Modnista ("Fashionable"), and Kozyavka ("Gnat").

Laika was the first dog (and the first animal) in space

On November 3rd, 1957, Sputnik 2 blasted into Earth orbit with a dog named Laika aboard. Laika, which is Russian for "Husky" or "Barker," had the real name of Kudryavka ("Little Curly"). In the U.S. she was eventually dubbed "Muttnik." Laika was a small, stray mongrel picked up from the street. She was hastily trained and put aboard in a metal carrier under the second Sputnik sphere. There was no time to work out any reentry strategy and Laika expired after a few hours. Sputnik 2 finally burned up in the outer atmosphere in April 1958.

Thor-Able

Back in the U.S., on April 23, 1958 a mouse was launched in a Thor-Able "Reentry 1" test as the first launch in the Mouse in Able (MIA) project. It was lost when the rocket was destroyed after launch from Cape Canaveral. The second launch in the series was MIA-2, or Laska, in a Thor-Able "Reentry 2" test on July 9, 1958. Laska endured 60G acceleration and 45 minutes of weightlessness before perishing. Wilkie, the third mouse in the MIA series, was lost at sea after the flight from Cape Canaveral on July 23, 1958. Fourteen mice were lost when the Jupiter rocket they were aboard was destroyed after launch from Cape Canaveral on September 16, 1959.

Gordo, a squirrel monkey, was catapulted 600 miles high in a Jupiter rocket, also on December 13, 1958, one year after the Soviets launched Laika. Gordo's capsule was never found in the Atlantic Ocean. He died on splashdown when a flotation mechanism failed, but Navy doctors said signals on his respiration and heartbeat proved humans could withstand a similar trip.

Able, an American-born rhesus monkey, and Baker, a South American squirrel monkey, followed on May 28, 1959, aboard an Army Jupiter missile. Launched in the nose cone, the two animals were carried to a 300-mile altitude, and both were recovered unharmed. However, Able died June 1 on the operating table from effects of anesthesia, as doctors were about to remove an electrode from under her skin. Baker died of kidney failure in 1984 at age 27.

Four black mice were launched on June 3, 1959, on Discoverer 3, part of the Corona program of U.S. spy satellites, which was launched from Vandenberg Air Force Base on a Thor Agena A rocket. This was the only Discoverer flight with an animal payload. The mice died when the Agena upper stage fired downward, driving the vehicle into the Pacific Ocean. The first try at launch was scrubbed after the telemetry indicated no sign of activity in the capsule and the first crew of four black mice was found dead. The mouse cages had been sprayed with krylon to cover rough edges, and the mice had found the krylon tastier than their formula and overdosed on it. The second try at launch with a backup mouse crew was halted when the humidity sensor in the capsule indicated 100-percent humidity. The capsule was opened up and it was discovered that the sensor was located underneath one of the mouse cages; it was unable to distinguish the difference between water and mouse urine. After the sensor was dried out, the launch proceeded.

Sam, a rhesus monkey, was one of the most well known monkeys of the space program. His name was an acronym for the U.S. Air Force S chool of A viation M edicine at Brooks Air Force Base, Texas. He was launched on December 4, 1959, housed in a cylindrical capsule within the Mercury spacecraft atop a Little Joe rocket in order to test the launch escape system (LES). Approximately one minute into the flight, traveling at a speed of 3685 mph, the Mercury capsule aborted from the Little Joe launch vehicle. After attaining an altitude of 51 miles, the spacecraft landed safely in the Atlantic Ocean. Sam was recovered, several hours later, with no ill effects from his journey. He was later returned to the colony in which he trained, where he died in November 1982 and his remains were cremated.

Miss Sam, another rhesus monkey and Sam's mate, was launched on January 21, 1960, for another test of the LES. The Mercury capsule attained a velocity of 1800 mph and an altitude of 9 miles. After landing in the Atlantic Ocean 10.8 miles downrange from the launch site, Miss Sam was also retrieved in overall good condition. She was also returned to her training colony until her death on an unknown date.

In the Soviet Union, meanwhile, testing was also taking place on more dogs. On July 28, 1960, Bars ("Panther" or "Lynx") and Lisichka ("Little Fox") were launched on a Korabl Sputnik, a prototype of the Vostok manned spacecraft. The booster exploded on launch, killing the two dogs. On August 19, 1960, Belka ("Squirrel") and Strelka ("Little Arrow") were launched on Sputnik 5 or Korabl Sputnik 2, along with a gray rabbit, 40 mice, 2 rats, and 15 flasks of fruit flies and plants. Strelka later gave birth to a litter of six puppies one of which was given to JFK as a gift for his children. Pchelka ("Little Bee") and Muska ("Little Fly") were launched onboard Sputnik 6 or Korabl Sputnik 3 on December 1, 1960 along with mice, insects, and plants. The capsule and animals burned up on re-entry. On December 22, 1960, soviet scientists attempted to launch Damka ("Little Lady") and Krasavka ("Beauty") on a Korabl Sputnik. However, the upper rocket stage failed and the launch was aborted. The dogs were safely recovered after their unplanned suborbital flight. On March 9, 1961, another Russian dog, Chernushka ("Blackie") was launched on Sputnik 9 or Korabl Sputnik 4. Chernushka was accompanied into space with a dummy cosmonaut, some mice, and a guinea pig. Zvezdochka ("Little Star") was launched onboard Sputnik 10 or Korabl Sputnik 5 on March 25, 1961.The dog went up with simulated cosmonaut "Ivan Ivanovich" and successfully tested the spacecraft's structure and systems.

On January 31, 1961, Ham, whose name was an acronym for H olloman A ero M ed, became the first chimpanzee in space, aboard the Mercury Redstone rocket on a sub-orbital flight very similar to Alan Shepard's. Ham was brought from the French Camaroons, West Africa, where he was born July 1957, to Holloman Air Force Base in New Mexico in 1959. The original flight plan called for an altitude of 115 miles and speeds ranging up to 4400 mph. However, due to technical problems, the spacecraft carrying Ham reached an altitude of 157 miles and a speed of 5857 mph and landed 422 miles downrange rather than the anticipated 290 miles. Ham performed well during his flight and splashed down in the Atlantic Ocean 60 miles from the recovery ship. He experienced a total of 6.6 minutes of weightlessness during a 16.5-minute flight. A post-flight medical examination found Ham to be slightly fatigued and dehydrated, but in good shape otherwise. Ham's mission paved the way for the successful launch of America's first human astronaut, Alan B. Shepard, Jr., on May 5, 1961. Upon the completion of a thorough medical examination, Ham was placed on display at the Washington Zoo in 1963 where he lived alone until September 25, 1980. He then was moved to the North Carolina Zoological Park in Asheboro. Upon his death on January 17, 1983, Ham's skeleton would be retained for ongoing examination by the Armed Forces Institute of Pathology. His other remains were respectfully laid to rest in front of the International Space Hall of Fame in Alamogordo, New Mexico.

Goliath, a one-and-a-half-pound squirrel monkey, was launched in an Air Force Atlas E rocket on November 10, 1961. The SPURT (Small Primate Unrestrained Test) monkey was killed when the rocket was destroyed 35 seconds after launch from Cape Canaveral.

Enos became the first chimp to orbit the earth on November 29, 1961, aboard a Mercury Atlas rocket. Although the mission plan originally called for three orbits, due to a malfunctioning thruster and other technical difficulties, flight controllers were forced to terminate Enos' flight after two orbits. Enos landed in the recovery area and was picked up 75 minutes after splashdown. He was found to be in good overall condition and both he and the Mercury spacecraft performed well. His mission concluded the testing for a human orbital flight, achieved by John Glenn on February 20, 1962. Enos died at Holloman Air Force Base of a non-space related case of dysentery 11 months after his flight.

On October 18, 1963, French scientists launched the first cat into space on a Veronique AGI sounding rocket No. 47. The cat, named Felix, was successfully retrieved after a parachute descent, but a second feline flight on October 24 ran into difficulties that prevented recovery.

Back in the Soviet Union, the dogs Veterok ("Breeze") and Ugoyok ("Little Piece Of Coal") were launched aboard Kosmos 110 by the Soviet Union on February 22, 1966. The flight was an evaluation of prolonged effects during space travel of radiation from the Van Allen Belts on animals. Twenty-one days in space still stand as a canine record and was only surpassed by humans in June 1974 with the flight of Skylab 2.

The year 1968 saw the U.S.S.R. turn once again to the animal kingdom for the first passengers of their new, manned moon ship. The first successful Zond ("probe") launch was on September 15, 1968, when Zond 5 was launched. A biological payload of turtles, wine flies, mealworms, plants, seeds, bacteria, and other living matter was included in the flight. On September 18, 1968, the spacecraft flew around the Moon. On September 21, 1968, the reentry capsule entered the earth's atmosphere, braked aerodynamically, and deployed parachutes at 7 km. The capsule splashed down in the Indian Ocean and was successfully recovered, but a failure of the reentry guidance system subjected the biological specimens to a ballistic 20G reentry. Zond 6 was launched on a lunar flyby mission on November 10, 1968. The spacecraft carried a biological payload similar to Zond 5. Zond 6 flew around the Moon on November 14, 1968. Unfortunately, the spacecraft lost a gasket on the return flight resulting in the loss of cabin atmosphere and destruction of the biological specimens.

From 1966 to 1969, the U.S. launched three missions in the Biosatellite series. A total of six flights were planned. The first mission in the Biosatellite series, Biosatellite I, was launched on December 14, 1966, from Cape Kennedy by a Delta rocket. The scientific payload, consisting of 13 select biology and radiation experiments, was exposed to microgravity during 45 hours of Earth-orbital flight. Experimental biology packages on the spacecraft contained a variety of specimens, including insects, frog eggs, microorganisms, and plants. Reentry into the Earth's atmosphere was not achieved because the retrorocket failed to ignite and the biosatellite was never recovered. Although not all the mission objectives were accomplished, the Biosatellite I experience provided technical confidence in the program because of excellent performance in most other areas.

Improvements were made in hardware, prelaunch tests, and procedures before Biosatellite II was launched on September 7, 1967 from Cape Kennedy. The planned three-day mission was recalled early because of the threat of a tropical storm in the recovery area, and because of a communication problem between the spacecraft and the tracking systems. It carried a biological payload similar to Biosatellite I. The primary objective of the Biosatellite II mission was to determine if organisms were more, or less, sensitive to ionizing radiation in microgravity than on Earth. To study this question, an artificial source of radiation (Strontium 85) was supplied to a group of experiments mounted in the forward part of the spacecraft.

The last spacecraft in the series, Biosatellite III, was launched on June 28, 1969. On board was a single, male, pig-tailed monkey (Macaca nemestrina) named Bonnie, weighing 6 kg, for a planned 30-day mission. The mission objective was to investigate the effect of space flight on brain states, behavioral performance, cardiovascular status, fluid and electrolyte balance, and metabolic state. However, after just under nine days in orbit, the mission was terminated because of the subject's deteriorating health. Bonnie died eight hours after he was recovered due to a heart attack brought about by dehydration.

After the manned lunar landing of Apollo 11, the role of animals was limited to the status of "biological payload." The range of species broadened to include rabbits, turtles, insects, spiders, fish, jellyfish, amoebae, and algae. Although they were still used in tests dealing with long-range health effects in space, tissue development, and mating in a zero-g environment, etc., animals no longer made the front pages. One exception to this was one of the last Apollo flights, Skylab 3, which launched on July 28, 1973. On board were Anita and Arabella, two common Cross spiders. Tests were set up to record the spiders' successful attempts to spin webs in space.

From 1973 to 1996, Russia, or its predecessor, the Soviet Union, launched a series of life sciences satellites called Bion. Research partners have included Austria, Bulgaria, Canada, China, the Commonwealth of Independent States, Czechoslovakia, East Germany, the European Space Agency, France, Germany, Hungary, Lithuania, Poland, Romania, Ukraine, and the United States. The Bion spacecraft is a modified Vostok type and is launched on a Soyuz rocket from the Plesetsk Kosmodrome in northern Russia.

Bion missions are typically put under the Kosmos umbrella name, used for a variety of different satellites including spy satellites. The first Bion launch was Kosmos 605 launched on October 31, 1973. The satellite carried tortoises, rats, insects, and fungi on a 22-day mission. Other missions have also carried plants, mold, quail eggs, fish, newts, frogs, cells, and seeds.

Starting with Bion 6 (Kosmos 1514), these missions have carried pairs of monkeys. Bion 6/Kosmos 1514 was launched December 14, 1983, and carried the monkeys Abrek and Bion on a five-day flight. Bion 7/Kosmos 1667 was launched July 10, 1985 and carried the monkeys Verny ("Faithful") and Gordy ("Proud") on a seven-day flight. Bion 8/Kosmos 1887 was launched September 29, 1987, and carried the monkeys Yerosha ("Drowsy") and Dryoma ("Shaggy") on a 13-day flight. Yerosha partially freed himself from his restraints and explored his orbital cage during the mission. On reentry, Bion 8 missed its touchdown point by 1850 miles, resulting in the death of several fish on board due to the frigid weather. Bion 9/Kosmos 2044 was launched September 15, 1989, and carried the monkeys Zhakonya and Zabiyaka ("Troublemaker") on a 14-day flight. Temperature problems onboard resulted in the loss of ant and earthworm experiments.

Bion 10/Kosmos 2229 was launched December 29, 1992, and carried the monkeys Krosh ("Tiny") and Ivasha on a 12-day flight. Bion 10 was recovered two days early due to thermal control problems that resulted in unacceptably high onboard temperatures. Seven of fifteen tadpoles onboard died as a result of the high temperatures. Both monkeys were treated for dehydration and recovered. One monkey also suffered weight loss when he went without food for three days. Bion 11 was launched December 24, 1996, and carried the monkeys Lapik and Multik ("Cartoon") on a 14-day flight. Tragically, Multik died the day after the capsule recovery during his post-landing medical operation and checkup. Multik's death raised new questions regarding the ethics of using animals for research. NASA has dropped out of participation in a planned Bion 12 mission.

From 1983 to the present day, the Space Shuttle has flown over two dozen Spacelab experimental packages in its payload bay. Life-science Spacelab missions have included experiments involving the human astronauts as well as the animals and insects carried on these missions. STS-51-B (Spacelab-3) launched April 29, 1985. STS-61-A (Spacelab-D1) launched October 30, 1985. STS-40 (Spacelab Life Sciences 1 SLS-1) launched June 5, 1991. STS-42 (International Microgravity Laboratory-1 IML-1) launched January 22, 1992. STS-47 (Spacelab-J), a joint venture between NASA and the National Space Development Agency of Japan (NASDA) launched September 12, 1992. STS-65 (IML-2) launched July 8, 1994. A biological payload record was set on April 17, 1998, when over two thousand creatures joined the seven-member crew of the shuttle Columbia (STS-90) for a sixteen-day mission of intensive neurological testing (NEUROLAB).

Over the past 50 years, American and Soviet scientists have utilized the animal world for testing. Despite losses, these animals have taught the scientists a tremendous amount more than could have been learned without them. Without animal testing in the early days of the human space program, the Soviet and American programs could have suffered great losses of human life. These animals performed a service to their respective countries that no human could or would have performed. They gave their lives and/or their service in the name of technological advancement, paving the way for humanity's many forays into space.

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Who Was the First Astronaut?

The first astronaut was either the Soviet Yuri Gagarin or the Soviet dog Laika, depending on whether the definition is restricted based on species. Both are remembered for their accomplishments and contributions to space travel.

Laika, a name that literally means "barker" and was based on her breed, was launched into space on 3 November 1957 on board Sputnik 2, becoming the first animal to orbit the Earth. This took place only a month after the first satellite, Sputnik, was launched, on 4 October 1957. Sputnik 2 was the second spacecraft launched into Earth orbit.

The dog was selected from the pound, and at one time was a homeless dog wandering the streets of Moscow. She died only a few hours after launch, due to stress and overheating from a malfunctioning thermal control unit. As the technology to return a payload to Earth was not available at the time, it was planned to put the canine astronaut to sleep with poisoned food on the 10th day of flight.

The cabin of Sputnik 2 included a life-support system with an oxygen generator, a fan that was supposed to activate when the temperature exceeded 59° F (15° C), gelatinous food for a 10-day flight, and a bag to collect waste. When some of the thermal insulation tore loose after separation of the last stage, the temperature of the cabin increased to 104° F (40° C), and Laika died within 5 to 7 hours after great stress. The precise cause of the dog's death was not made public until decades later.

As satellite and space technology rapidly progressed, the Soviet Union once again decided to pioneer the way forward in space by launching the first human astronaut. Yuri Gagarin was launched into space on 12 April 1961, about three and a half years after the launch of Sputnik. Traveling on board Vostok 1, Gagarin orbited the Earth just once, which took 108 minutes.

Gagarin then ejected from the capsule, about 4.35 miles (7 km) above the ground, parachuting to Earth a few hundred miles (km) away from the launch site in Kazakhstan. Some villagers witnessed Vostok 1 hit the ground near where Gagarin landed with his parachute. Being the world's first astronaut, Gagarin instantly became an international celebrity.

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What causes gravitational force in the universe?

Gravity is one the four fundamental forces of the universe and is considered a noncontact force. It is what holds the planets in orbit as well as the very universe itself. It is what keeps us from floating off into space and plays a crucial role in almost every nature process from the ocean tides to the body’s circulatory system. However what causes gravity? What is the mechanism that makes it work? Physicists have only partially answered this question. The first person to comprehensively describe it was Isaac Newton.


Newton gave us the foundations of Physics, Classical Kinematics. Isaac Newton used the universal law of gravitation to describe how gravity works. Thanks to him we now any two objects in the universe that have mass exert a gravitational pull on each other. The greater the mass and the closer the two objects are, the stronger the force of gravity. However this only described the phenomenon in party. It basically was a more detailed description than just something makes any object that is unsupported to fall to the ground. Newton took the next step in describing it with his Theory of Relativity.


Einstein hypothesized that space and time were one and the same and served as the fabric of the universe. He stated that gravity was simply a curvature in space-time created by a mass object pretty much in the same way a piece of cloth would be curved if it was stretched out and a heft object was placed on it. This curvature in space created by an object with greater mass than the objects surrounding it would cause these objects of lesser mass to fall toward the more massive object.

Even then this only described gravity on the large scale. Newton’s Law of Universal Gravitation correctly states that gravity affected every thing with mass in the universe. This is where quantum physics came in. Quantum physics introduced the existence of even smaller particles than neutrons, electrons, and protons to describe what seemed to be exceptions to classical physics when the interaction of matter is viewed on the micro scale. Quantum physics proposed a theoretical particle called the graviton that controls gravity.

That brings us to our current understanding. Gravity still remains one of the biggest mysteries of physics and the biggest obstacle to a universal theory that describes the functions of every interaction in the universe accurately. If we could fully understand the mechanics behind it, new opportunities in aeronautics and other fields would appear.

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Universal Law of Gravitation

One of Sir Issac Newton’s biggest contributions to physics and the larger body of science was the universal law of gravitation. Without it we can’t explain the classical motion of objects on Earth or in space. We would not have gained the ability to fly or even go into space. The understanding of gravity is basically the beggining of understanding classical mechanics and physics.

The story of how Sir Isaac Newton has now become one of the great myths of science. Every grade schooler of suitable age would be able to tell you how Newton discovered gravity when an apple fell on his head from the tree he sat under. In truth scientist had been doing gravity experiments long before Newton. One such scientist was the famous Renaissance Astronomer Galileo  His experiments determined that all objects fall towards the earth with the same acceleration and velocity regardless of their mass. The only difference is air resistance.

Sir Issac Newton took it a step further. He saw that gravity was not just a phenomenon found on Earth, but a fundamental force that helped hold the universe together. His state that gravity could exists between any to objects with mass and the relationships of gravity’s strength to both objects mass and distance of separation were major steps for classical mechanics.

However there are still holes in the universal law of gravitation. First we don’t know what gravity is. It is a question similar to whether light is a particle or a wave. The question is whether gravity has a particle like other fundamental forces in the standard model or is simple the shape geometry of space time near objects with mass. The reason for the debate is that at high energies the law of gravity doesn't behave properly and give the expected values. One explanation is that physics uses to different types of theories that are not usually linked together well. Classical mechanics deals with the large scale movements of objects while quantum physics deals with motions on the atomic and subatomic level. Each of these different frames of reference have different rules so don’t always act the same. Gravity is on of the forces yet to fit neatly into both points of view.

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Is it Safe to Be Around Sources of Radiation? How Can You Work Safely Around Radiation or Contamination?

How Can You Work Safely Around Radiation or Contamination?

You can work safely around radiation and/or contamination by following a few simple precautions:

1. Use time, distance, shielding, and containment to reduce exposure.
    
2. Wear dosimeters (e.g., film or TLD badges) if issued.
    
3. Avoid contact with the contamination.
    
4. Wear protective clothing that, if contaminated, can be removed.
    
5. Wash with nonabrasive soap and water any part of the body that may have come in contact with the contamination.
    
6. Assume that all materials, equipment, and personnel that came in contact with the contamination are contaminated. Radiological monitoring is recommended before leaving the scene.
    

Is it Safe to Be Around Sources of Radiation?

A single high-level radiation exposure (i.e., greater than 10,000 mrem) delivered to the whole body over a very short period of time may have potential health risks. From follow-up of the atomic bomb survivors, we know acutely delivered very high radiation doses can increase the occurrence of certain kinds of disease (e.g., cancer) and possibly negative genetic effects. To protect the public and radiation workers (and environment) from the potential effects of chronic low-level exposure (i.e., less than 10,000 mrem), the current radiation safety practice is to prudently assume similar adverse effects are possible with low-level protracted exposure to radiation. Thus, the risks associated with low-level medical, occupational, and environmental radiation exposure are conservatively calculated to be proportional to those observed with high-level exposure. These calculated risks are compared to other known occupational and environmental hazards, and appropriate safety standards and policies have been established by international and national radiation protection organizations (e.g., International Commission on Radiological Protection and National Council on Radiation Protection and Measurements) to control and limit potential harmful radiation effects.

Both public and occupational regulatory dose limits are set by federal agencies (i.e., Environmental Protection Agency, Nuclear Regulatory Commission, and Department of Energy) and state agencies (e.g., agreement states) to limit cancer risk. Other radiation dose limits are applied to limit other potential biological effects with workers' skin and lens of the eye.

Annual Radiation Dose Limits	Agency
Radiation Worker - 5,000 mrem	(NRC, "occupationally" exposed)
General Public - 100 mrem	(NRC, member of the public)
General Public - 25 mrem	(NRC, D&D all pathways)
General Public - 10 mrem	(EPA, air pathway)
General Public - 4 mrem	(EPA, drinking-water pathway)

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How Can You Detect Radiation?

Radiation cannot be detected by human senses. A variety of handheld and laboratory instruments is available for detecting and measuring radiation. The most common handheld or portable instruments are:

1. Geiger Counter, with Geiger-Mueller (G-M) Tube or Probe — A G-M tube is a gas-filled device that, when a high voltage is applied, creates an electrical pulse when radiation interacts with the wall or gas in the tube. These pulses are converted to a reading on the instrument meter. If the instrument has a speaker, the pulses also give an audible click. Common readout units are roentgens per hour (R/hr), milliroentgens per hour (mR/hr), rem per hour (rem/hr), millirem per hour (mrem/hr), and counts per minute (cpm). G-M probes (e.g., "pancake" type) are most often used with handheld radiation survey instruments for contamination measurements. However, energy-compensated G-M tubes may be employed for exposure measurements. Further, often the meters used with a G-M probe will also accommodate other radiation detection probes. For example, a zinc sulfide (ZnS) scintillator probe, which is sensitive to just alpha radiation, is often used for field measurements where alpha-emitting radioactive materials need to be measured.
    
2. MicroR Meter, with Sodium Iodide Detector — A solid crystal of sodium iodide creates a pulse of light when radiation interacts with it. This pulse of light is converted to an electrical signal by a photomultiplier tube (PMT), which gives a reading on the instrument meter. The pulse of light is proportional to the amount of light and the energy deposited in the crystal. These instruments most often have upper and lower energy discriminator circuits and, when used correctly as single-channel analyzers, can provide information on the gamma energy and identify the radioactive material. If the instrument has a speaker, the pulses also give an audible click, a useful feature when looking for a lost source. Common readout units are microroentgens per hour (μR/hr) and/or counts per minute (cpm). Sodium iodide detectors can be used with handheld instruments or large stationary radiation monitors. Special plastic or other inert crystal "scintillator" materials are also used in place of sodium iodide.
    
3. Portable Multichannel Analyzer — A sodium iodide crystal and PMT described above, coupled with a small multichannel analyzer (MCA) electronics package, are becoming much more affordable and common. When gamma-ray data libraries and automatic gamma-ray energy identification procedures are employed, these handheld instruments can automatically identify and display the type of radioactive materials present. When dealing with unknown sources of radiation, this is a very useful feature.
    
   
   
   
   
   
   
   
   
4. Ionization (Ion) Chamber — This is an air-filled chamber with an electrically conductive inner wall and central anode and a relatively low applied voltage. When primary ion pairs are formed in the air volume, from x-ray or gamma radiation interactions in the chamber wall, the central anode collects the electrons and a small current is generated. This in turn is measured by an electrometer circuit and displayed digitally or on an analog meter. These instruments must be calibrated properly to a traceable radiation source and are designed to provide an accurate measure of absorbed dose to air which, through appropriate conversion factors, can be related to dose to tissue. In that most ion chambers are "open air," they must be corrected for change in temperature and pressure. Common readout units are milliroentgens and roentgen per hour (mR/hr or R/hr). (Note: For practical purposes, consider the roentgen, rad, and the rem to be equal with gamma or x rays. So, 1 mR/hr is equivalent to 1 mrem/hr.)
    
5. Neutron REM Meter, with Proportional Counter — A boron trifluoride or helium-3 proportional counter tube is a gas-filled device that, when a high voltage is applied, creates an electrical pulse when a neutron radiation interacts with the gas in the tube. The absorption of a neutron in the nucleus of boron-10 or helium-3 causes the prompt emission of a helium-4 nucleus or proton respectively. These charged particles can then cause ionization in the gas, which is collected as an electrical pulse, similar to the G-M tube. These neutron-measuring proportional counters require large amounts of hydrogenous material around them to slow the neutron to thermal energies. Other surrounding filters allow an appropriate number of neutrons to be detected and thus provide a flat-energy response with respect to dose equivalent. The design and characteristics of these devices are such that the amount of secondary charge collected is proportional to the degree of primary ions produced by the radiation. Thus, through the use of electronic discriminator circuits, the different types of radiation can be measured separately. For example, gamma radiation up to rather high levels is easily rejected in neutron counters.
    
6. Radon Detectors — A number of different techniques are used for radon measurements in home or
   
   occupational settings (e.g., uranium mines). These range from collection of radon decay products on an air filter and counting, exposing a charcoal canister for several days and performing gamma spectroscopy for absorbed decay products, exposure of an electret ion chamber and read-out, and long-term exposure of CR39 plastic with subsequent chemical etching and alpha track counting. All these approaches have different advantages and disadvantages which should be evaluated prior to use.

The most common laboratory instruments are:

1. Liquid Scintillation Counters — A liquid scintillation counter (LSC) is a traditional laboratory
   
   instrument with two opposing PMTs that view a vial that contains a sample and liquid scintillator fluid, or cocktail. When the sample emits a radiation (often a low-energy beta) the cocktail itself, being the detector, causes a pulse of light. If both PMTs detect the light in coincidence, the count is tallied. With the use of shielding, cooling of PMTs, energy discrimination, and this coincidence counting approach, very low background counts can be achieved, and thus low minimum detectable activities (MDA). Most modern LSC units have multiple sample capability and automatic data acquisition, reduction, and storage.
    
2. Proportional Counter — A common laboratory instrument is the standard proportional counter with
   
   sample counting tray and chamber and argon/methane flow through counting gas. Most units employ a very thin (microgram/cm2) window, while some are windowless. Shielding and identical guard chambers are used to reduce background and, in conjunction with electronic discrimination, these instruments can distinguish between alpha and beta radiation and achieve low MDAs. Similar to the LSC units noted above, these proportional counters have multiple sample capability and automatic data acquisition, reduction, and storage. Such counters are often used to count smear/wipe or air filter samples. Additionally, large-area gas flow proportional counters with thin (milligram/cm2) mylar windows are used for counting the whole body and extremities of workers for external contamination when exiting a radiological control area.
    
   
   
   
   
   
3. Multichannel Analyzer System — A laboratory MCA with a sodium iodide crystal and PMT
   
   (described above), a solid-state germanium detector, or a silicon-type detector can provide a powerful and useful capability for counting liquid or solid matrix samples or other prepared extracted radioactive samples. Most systems are used for gamma counting, while some silicon detectors are used for alpha radiation. These MCA systems can also be utilized with well-shielded detectors to count internally deposited radioactive material in organs or tissue for bioassay measurements. In all cases, the MCA provides the capability to bin and tally counts by energy and thus identify the emitter. Again, most systems have automatic data 

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