As humans moved from continent to continent, large animals that had thrived for millions of years began to disappear-mastodons in North America, giant kangaroos in Australia, dwarf elephants in Europe. Mastodons may have been some of the earliest victims. Today, according to many biologists, we’re in the midst of a sixth great extinction. He asked Lewis and Clark to keep an eye out for them. Thomas Jefferson saw mastodon bones from Kentucky, for example, and concluded that the giant animals must still be living somewhere in the interior of the continent. The concept of extinction took a while to sink in. Paleontologists have identified five points in Earth’s history when, for whatever reason (asteroid impact, volcanic eruptions and atmospheric changes are the main suspects), mass extinctions eliminated many or most species. There have been mass extinctions in the past, and we’re probably in one now. Even in the 21st century, it’s quite possible to die of consumption.ģ. Even tuberculosis, the disease that killed Frederic Chopin and Henry David Thoreau, is making a comeback, in part because some strains of the bacterium have developed multi-drug resistance. And new diseases keep jumping from animals to humans-ebola from apes, SARS from masked palm civets, hantavirus from rodents, bird flu from birds, swine flu from swine. Hospitals are infested with antibiotic-resistant Staphylococcus bacteria that can turn a small cut into a limb- or life-threatening infection. The influenza virus mutates so quickly that last year’s vaccination is usually ineffective against this year’s bug. But some microbes are evolving faster than we can find ways to fight them. Scripture said that the Sun revolved around the Earth, and the Holy Office of the Inquisition found Galileo guilty of heresy for saying otherwise.Īntibiotics and vaccines have saved millions of lives without these wonders of modern medicine, many of us would have died in childhood of polio, mumps or smallpox. More dangerous than defying common sense, though, was Galileo’s defiance of the Catholic Church. He used a telescope to provide evidence for the heliocentric theory, and some of his contemporaries were so disturbed by what the new invention revealed-craters on a supposedly perfectly spherical moon, other moons circling Jupiter-that they refused to look through the device. Galileo got more grief for the idea than Copernicus did. Very few scholars saw it as a real description of the universe.” “It would take several generations to sink in. … his contemporaries found his massive logical leap “patently absurd,” says Owen Gingerich of the Harvard-Smithsonian Center for Astrophysics. When Copernicus proposed that the Earth and other planets instead orbit the Sun, Anyone can plainly see that the Sun and stars rise in the east, sweep across the sky and set in the west the Earth feels stable and stationary. We’ve had more than 400 years to get used to the idea, but it’s still a little unsettling. The Earth is not the center of the universe. Here are ten of the biggest threats to our peace of mind.ġ. But big scientific discoveries are by nature counterintuitive and sometimes shocking. Science can be glorious it can bring clarity to a chaotic world.
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