The Perseids appear like clockwork each year when Earth passes through a giant cloud of debris left in the wake of comet Swift-Tuttle. Hitting the atmosphere at speeds of almost 100,000 miles (160,000 kilometers) an hour, the meteors burn up and produce streaks of light that each last just a fraction of a second.
Compact, ultra-blue galaxies spied for the first time in the deep universe are the most distant—and therefore the earliest—galaxies anyone has ever seen, astronomers announced in January.
These galaxies started forming just 500 million years after the big bang, which is thought to have occurred around 13.7 billion years ago. That pushes back the known start of galaxy formation by about 1.5 billion years.
Picture courtesy NASA, ESA, G. Illingworth and R. Bouwens (University of California, Santa Cruz), and the HUDF09 Team
8. Astronauts' Fingernails Falling Off
Astronauts with wider hands are more likely to have their fingernails fall off after working or training in space suit gloves, according to a study released in September.
In fact, fingernail trauma and other hand injuries—no matter your hand size—are collectively the number one nuisance for spacewalkers. For now, the only solutions are to apply protective dressings, keep nails trimmed short, or do some extreme preventative maintenance.
"I have heard of a couple people who've removed their fingernails in advance of an EVA"—aka a spacewalk—a study co-author said.
A theory for the origins of the universe predicts that time itself will end in just five billion years, according to a paper released in October.
The prediction comes from the theory of eternal inflation, which says our universe is just one of an infinite number of universes. This creates problems with calculating probabilities, which theorists circumvent using a mathematical technique called cutoffs.
But cutoffs have an overlooked consequence, the study authors say: They show when time in our universe will come to an end.
Although the announcement later proved controversial, astronomers made waves in September when they said they had found a planet outside our solar system with an atmosphere, temperate regions, and—crucially—liquid water, which is considered vital for life as we know it.
Roughly three times more massive than Earth, the planet Gliese 581g is tidally locked to its star, which means that one side is perpetually basked in daylight and the other is in constant darkness.
Aliens, if they exist, are most likely to live along the line between shadow and light, a temperate region known as the terminator, the scientists said.
A large meteor blazed across the midwestern U.S. sky in April, igniting over Wisconsin, Iowa, Illinois, and Missouri around 10:15 p.m., local time. The fireball briefly turned night to green-tinged day and unleashed a sonic boom heard for hundreds of miles around.
Based on video of the event, astronomer Mark Hammergren, of Chicago's Adler Planetarium, told National Geographic News he thought the space rock that birthed the fireball may have been up to 6 feet (1.8 meters) wide and may have weighed a thousand pounds (453 kilograms) or more.
In early August cameras aboard NASA's Solar Dynamics Observatory (SDO) captured an eruption on the sun's surface that hurled tons of plasma—charged gas—directly toward Earth in an event called a coronal mass ejection.
Late January saw the biggest full moon of 2010 rising in the east with a bright sidekick: Bright, red Mars appeared just to the left of the supersize moon.
January's full moon appeared 30 percent brighter and 14 percent larger than any other full moon of the year, because our cosmic neighbor was actually closer to Earth than usual, reaching a distance of just 221,577 miles (356,593 kilometers).
Like part of a cosmic Russian doll, our universe may be nested inside a black hole that is itself part of a larger universe.
In turn, all the black holes found so far in our universe—from the microscopic to the supermassive—may be doorways into alternate realities.
According to a mind-bending study released in April, a black hole is actually a tunnel between universes—a type of wormhole. The matter the black hole attracts doesn't collapse into a single point, as has been predicted, but rather gushes out a "white hole" at the other end of the black one, the theory goes.