How Many People Have Ever Lived On Earth?
SOME SAY THAT IT IS 106,456,367,669*
*ONE ESTIMATE:
| Year | Population | Births per 1,000 | Births Between Benchmarks |
| 50,000 B.C. | 2 | - | - |
| 8000 B.C. | 5,000,000 | 80 | 1,137,789,769 |
| 1 A.D. | 300,000,000 | 80 | 46,025,332,354 |
| 1200 | 450,000,000 | 60 | 26,591,343,000 |
| 1650 | 500,000,000 | 60 | 12,782,002,453 |
| 1750 | 795,000,000 | 50 | 3,171,931,513 |
| 1850 | 1,265,000,000 | 40 | 4,046,240,009 |
| 1900 | 1,656,000,000 | 40 | 2,900,237,856 |
| 1950 | 2,516,000,000 | 31-38 | 3,390,198,215 |
| 1995 | 5,760,000,000 | 31 | 5,427,305,000 |
| 2002 | 6,215,000,000 | 23 | 983,987,500 |
| Number who have ever been born | 106,456,367,669 |
| World population in mid-2002 | 6,215,000,000 |
| Percent of those ever born who are living in 2002 | 5.8 |
Source: Population Reference Bureau estimates.
One complicating factor is the pattern of population growth. Did it rise to some level and then fluctuate wildly in response to famines and changes in climate? Or did it grow at a constant rate from one point to another? We cannot know the answers to these questions, although paleontologists have produced a variety of theories. For the purposes of this exercise, it was assumed that a constant growth rate applied to each period up to modern times. Birth rates were set at 80 per 1,000 per year through 1 A.D. and at 60 per 1,000 from 2 A.D. to 1750. Rates then declined to the low 30s by the modern period. (For a brief bibliography of sources consulted in the course of this alchemy, see "For More Information.")
This semi-scientific approach yields an estimate of about 106 billion births since the dawn of the human race. Clearly, the period 8000 B.C. to 1 A.D. is key to the magnitude of our number, but, unfortunately, little is known about that era. Some readers may disagree with some aspects — or perhaps nearly all aspects — of the table, but at least it offers one approach to this elusive issue. If we were to make any guess at all, it might be that our method underestimates the number of births to some degree. The assumption of constant population growth in the earlier period may underestimate the average population size at the time. And, of course, pushing the date of humanity's arrival on the planet before 50,000 B.C. would also raise the number, although perhaps not by terribly much.
So, our estimate here is that about 5.8 percent of all people ever born are alive today. That's actually a fairly large percentage when you think about it.
Another Estimate given from http://www.math.hawaii.edu/~ramsey/People.html
| Year | People | People-Years Since
|
| -1000,000 | 2 | 0 |
|
| 7,500,000 | 4.91* 1011 |
| 0 | 300,000,000 | 7.14 * 1011 |
| 1650 | 507,500,000 | 6.51 * 1011 |
| 1750 | 795,000,000 | 6.41 * 1010 |
| 1800 | 969,000,000 | 4.40 * 1010 |
| 1850 | 1,265,000,000 | 5.55 * 1010 |
| 1900 | 1,656,000,000 | 7.26 * 1010 |
| 1950 | 2,513,000,000 | 1.027 * 1011 |
| 1960 | 3,027,000,000 | 2.76 * 1010 |
| 1970 | 3,678,000,000 | 3.34 * 1010 |
| 1980 | 4,415,000,000 | 4.04 * 1010 |
| 1990 | 5,275,000,000 | 4.83 * 1010 |
| 2000 | 6,199,000,000 | 5.72 * 1010 |
| | ||
The total of the entries of the last column is about 2,402 billion person-years (2,402,000,000,000). If one divides by 25 as an estimate of average lifespan, one estimates that 96,100,000,000 people have lived on the earth.
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What are the chances of us being hit by an asteroid and when would it happen?
SOURCE: http://imagine.gsfc.nasa.gov/docs/ask_astro/answers/danger.html
The first thing to remember is that space is big and empty. Which makes the chance that we will be hit by anything from space very small. In much of space, for example, large-sized objects are hundreds or thousands of light years apart. Even the asteroid belt has so much space in it, that we can send space probes through it without any problems. The asteroids in the belt are spread over a ring that is more than a billion kilometers in circumference, more than 100 million kilometers 
wide, and millions of kilometers thick.
Here's what JPL's Near Earth Asteroid Tracking team has to say:
"The most dangerous asteroids, capable of a global disaster, are extremely rare. The threshold size is believed to be 1/2 to 1 km. These bodies impact the Earth only once every 1,000 centuries on average. Comets in this size range are thought to impact even less frequently, perhaps once every 5,000 centuries or so."
The Asteroid and Impact Hazard page says:
"The threshold for an impact that causes widespread global mortality and threatens civilization almost certainly lies between about 0.5 and 5 km diameter, perhaps near 2 km. Impacts of objects this large occur from one to several times per million years.
"Because the risk of such an 
impact happening in the near future is very low, the nature of the impact hazard is unique in our experience. Nearly all hazards we face in life actually happen to someone we know, or we learn about them from the media, whereas no large impact has taken place within the total span of human history... It is this juxtaposition of the small probability of occurrence balanced against the enormous consequences if it does happen that makes the impact hazard such a difficult and controversial topic."
This is a difficult issue because an impact would pose enormous risk, yet because the odds of it occurring within our lifetimes is so low, it is unnecessary to run around believing that the sky is falling. There are two things to consider: one is that there are many organizations with telescopes trained to the sky, watching and tracking asteroids and comets, compiling a list of potentially hazardous objects to keep an eye on. Many of these objects are decades away from approaching the Earth which gives us a lot of time to track them in order to accurately predict their orbits.
How Many Gay People Are There?
Gay Population Statistics
By Ramon Johnson, About.com Guide
See More About:
© Dimitri Vervitsiotis/Getty
How many gay people are there in the United States?
The Williams Institute at the UCLA School of Law, a sexual orientation law and public policy think tank, estimates that there are 8.8 million gay, lesbian, and bisexual persons in the U.S based on the 2005/2006 American Community Survey, an extension of the U.S. Census (Gary J. Gates, 2006, "Same-Sex Couples and the Gay, Lesbian, Bisexual Population: New Estimates from the American Community Survey").
Why is this number an estimate?
The number of LGB persons in the U.S. is subjective. Studies pointing to the statistics are estimates at best. The most widely accepted statistic is that 1 in ever 10 individuals is LGB; however research shows that the number may be more like 1 in 20.
Of course, this all depends on one's definition of gay (which may vary by study) and the participants willingness to identify as gay, bi, lesbian or transgender. So, why can't the actual number of GLB people be counted? There are many things to consider when trying to count the number of GLBT persons.
What do the experts say?
When asked about GLB population statistics, Gary J. Gates, a Senior Research Fellow at The Williams Institute on Sexual Orientation Law and Public Policy, says:
"That's the single question that I'm asked the most. The answer is unfortunately not simple. I'll respond with a question. What do you mean when you use the word 'gay'? If you mean people who identify as gay, lesbian, or bisexual in a survey, then the answer is that it's likely not one in ten, but closer to one in twenty. A recent government survey found that 4 percent of adults aged 18-45 identified as 'homosexual' or 'bisexual.' A similar proportion of voters identify as GLB. If you define gay as having same-sex attractions or behaviors, you do get higher proportions that are a bit closer to the one in ten figure." Read more of my interview with Gary Gates.
2012: Six End-of-the-World
Myths Debunked
Brian Handwerk
for National Geographic News
November 6, 2009
The end of the world is near—December 21, 2012, to be exact—according to theories based on a purported ancient Maya prediction and fanned by the marketing machine behind the soon-to-be-released 2012 movie.
But could humankind really meet its end in 2012—drowned in apocalyptic floods, walloped by a 
secret planet, seared by an angry sun, or thrown overboard by speeding continents?
And did the ancient Maya—whose empire peaked between A.D. 250 and 900 in what is now Mexico and Central America—really predict the end of the world in 2012?
At least one aspect of the 2012, end-of-the-world hype is, for some people, all too real: the fear.
NASA's Ask an Astrobiologist Web site, for example, has received thousands of questions regarding the 2012 doomsday predictions—some of them disturbing, according to David Morrison, senior scientist with the NASA Astrobiology Institute.
"A lot of [the submitters] are people who are genuinely frightened," Morrison said.
"I've had two teenagers who were considering killing themselves, because they didn't want to be around when the world ends," he said. "Two women in the last two weeks said they were contemplating killing their children and themselves so they wouldn't have to suffer through the end of the world."
(Related gallery: "Apocalypse Pictures—Ten Failed Doomsday Prophecies.")
Fortunately, with the help of scientists like Morrison, most of the predicted 2012 cataclysms are easily explained away.
2012 MYTH 1
Maya Predicted End of the World in 2012
The Maya calendar doesn't end in 2012, as some have said, and the ancients never viewed that year as the time of the end of the world, archaeologists say.
But December 21, 2012, (give or take a day) was nonetheless momentous to the Maya.
"It's the time when the largest grand cycle in the Mayan calendar—1,872,000 days or 5,125.37 years—overturns and a new cycle begins," said Anthony Aveni, a Maya expert and archaeoastronomer at Colgate University in Hamilton, New York.
The Maya kept time on a scale few other cultures have considered.
During the empire's heyday, the Maya invented the Long Count—a lengthy circular calendar that "transplanted the roots of Maya culture all the way back to creation itself," Aveni said.
During the 2012 winter solstice, time runs out on the current era of the Long Count calendar, which began at what the Maya saw as the dawn of the last creation period: August 11, 3114 B.C. The Maya wrote that date, which preceded their civilization by thousands of years, as Day Zero, or 13.0.0.0.0.
In December 2012 the lengthy era ends and the complicated, cyclical calendar will roll over again to Day Zero, beginning another enormous cycle.
"The idea is that time gets renewed, that the world gets renewed all over again—often after a period of stress—the same way we renew time on New Year's Day or even on Monday morning," said Aveni, author of The End of Time: The Maya Mystery of 2012.
2012 MYTH 2
Breakaway Continents Will Destroy Civilization
In some 2012 doomsday prophecies, the Earth becomes a deathtrap as it undergoes a "pole shift."
The planet's crust and mantle will suddenly shift, spinning around Earth's liquid-iron outer core like an orange's peel spinning around its fleshy fruit. (See what Einstein had to say about pole shifts.)
2012, the movie, envisions a Maya-predicted pole shift, triggered by an extreme gravitational pull on the planet—courtesy of a rare "galactic alignment"—and by massive solar radiation destabilizing the inner Earth by heating it.
Breakaway oceans and continents dump cities into the sea, thrust palm trees to the poles, and spawn earthquakes, tsunamis, volcanic eruptions, and other disasters. (Interactive: pole shift theories illustrated.)
Scientists dismiss such drastic scenarios, but some researchers have speculated that a subtler shift could occur—for example, if the distribution of mass on or inside the planet changed radically, due to, say, the melting of ice caps.
Princeton University geologist Adam Maloof has extensively studied pole shifts, and tackles this 2012 myth in 2012: Countdown to Armageddon, a National Geographic Channel documentary airing Sunday, November 8. (The National Geographic Society owns National Geographic News and part-owns the National Geographic Channel.)
Maloof says magnetic evidence in rocks confirm that continents have undergone such drastic rearrangement, but the process took millions of years—slow enough that humanity wouldn't have felt the motion (quick guide to plate tectonics).
2012 MYTH 3
Galactic Alignment Spells Doom
Some sky-watchers believe 2012 will close with a "galactic alignment," which will occur for the first time in 26,000 years (for example, see the Web site Alignment 2012).
In this scenario, the path of the sun in the sky would appear to cross through what, from Earth, looks to be the midpoint of our galaxy, the Milky Way, which in good viewing conditions appears as a cloudy stripe across the night sky.
Some fear that the lineup will somehow expose Earth to powerful unknown galactic forces that will hasten its doom—perhaps through a "pole shift" (see above) or the stirring of the supermassive black hole at our galaxy's heart.
Others see the purported event in a positive light, as heralding the dawn of a new era in human consciousness.
NASA's Morrison has a different view.
"There is no 'galactic alignment' in 2012," he said, "or at least nothing out of the ordinary."
He explained that a type of "alignment" occurs during every winter solstice, when the sun, as seen from Earth, appears in the sky near what looks to be the midpoint of the Milky Way.
Horoscope writers may be excited by alignments, Morrison said. But "the reality is that alignments are of no interest to science. They mean nothing," he said. They create no changes in gravitational pull, solar radiation, planetary orbits, or anything else that would impact life on Earth.
The speculation over alignments isn't surprising, though, he said.
"Ordinary astronomical phenomena are imbued with a sense of threat by people who already think the world is going to end."
Regarding galactic alignments, University of Texas Maya expert David Stuart writes on his blog that "no ancient Maya text or artwork makes reference to anything of the kind."
Even so, the end date of the current Long Count cycle—winter solstice 2012—may be evidence of Maya astronomical skill, said Aveni, the archaeoastronomer.
"I don't rule out the likelihood that astronomy played a role" in the selection of 2012 as the cycle's terminus, he said.
Maya astronomers built observatories and, by observing the night skies and using mathematics, learned to accurately predict eclipses and other celestial phenomena. Aveni notes that the start date of the current cycle was likely tied to a solar zenith passage, when the sun crosses directly overhead, and its terminal date will fall on a December solstice, perhaps by design.
These choices, he said, may indicate that the Maya calendar is tied to seasonal agricultural cycles central to ancient survival.
2012 MYTH 4
Planet X Is on a Collision Course With Earth
Some say it's out there: a mysterious Planet X, aka Nibiru, on a collision course with Earth—or at least a disruptive flyby.
A direct hit would obliterate Earth, it's said. Even a near miss, some fear, could shower Earth with deadly asteroid impacts hurled our way by the planet's gravitational wake.
Could such an unknown planet really be headed our way in 2012, even just a little bit?
Well, no.
"There is no object out there," NASA astrobiologist Morrison said. "That's probably the most straightforward thing to say."
The origins of this theory actually predate widespread interest in 2012. Popularized in part by a woman who claims to receive messages from extraterrestrials, the Nibiru doomsday was originally predicted for 2003.
"If there were a planet or a brown dwarf or whatever that was going to be in the inner solar system three years from now, astronomers would have been studying it for the past decade and it would be visible to the naked eye by now," Morrison said.
"It's not there."
2012 MYTH 5
Solar Storms to Savage Earth
In some 2012 disaster scenarios, our own sun is the enemy.
Our friendly neighborhood star, it's rumored, will produce lethal eruptions of solar flares, turning up the heat on Earthlings.
Solar activity waxes and wanes according to approximately 11-year cycles. Big flares can indeed damage communications and other Earthly systems, but scientists have no indications the sun, at least in the short term, will unleash storms strong enough to fry the planet.
"As it turns out the sun isn't on schedule anyway," NASA astronomer Morrison said. "We expect that this cycle probably won't peak in 2012 but a year or two later." (See "Sun Oddly Quiet—Hints at Next 'Little Ice Age'?")
2012 MYTH 6
Maya Had Clear Predictions for 2012
If the Maya didn't expect the end of time in 2012, what exactly did they predict for that year?
Many scholars who've pored over the scattered evidence on Maya monuments say the empire didn't leave a clear record predicting that anything specific would happen in 2012.
The Maya did pass down a graphic—though undated—end-of-the-world scenario, described on the final page of a circa-1100 text known as the Dresden Codex. The document describes a world destroyed by flood, a scenario imagined in many cultures and probably experienced, on a less apocalyptic scale, by ancient peoples (more on the Dresden Codex).
Aveni, the archaeoastronomer, said the scenario is not meant to be read literally—but as a lesson about human behavior.
He likens the cycles to our own New Year period, when the closing of an era is accompanied by frenetic activities and stress, followed by a rebirth period, when many people take stock and resolve to begin living better.
In fact, Aveni says, the Maya weren't much for predictions.
"The whole timekeeping scale is very past directed, not future directed," he said. "What you read on these monuments of the Long Count are events that connected Maya rulers with ancestors and the divine.
"The farther back you can plant your roots in deep time the better argument you can make that you're legit," Aveni said. "And I think that's why these Maya rulers were using Long Count time.
"It's not about a fixed prediction about what's going to happen."
THE PROBLEM IS IN RELIGIONS
There are a lot of religions out there that go around preaching the end of the world, Judgment Day, Armageddon, and since people have faith in these religions they are confronted with the theory, therefore adding more fuel to the fire. How many of these cults have we seen predicting a certain date to have the end of the world and then that day comes and nothing happens? There are hundreds if not thousands. We just have to keep in mind that some of these have caused real havoc and destruction all by themselves, sometimes being the cause of mass suicides even.
SOURCE; http://gaylife.about.com/od/comingout/a/population.htm
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http://news.nationalgeographic.com/news/2009/11/091106-2012-end-of-world-myths.html
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