June 30 will be the longest day in three years, because you’ll get one extra second in your day—a leap second. The International Earth Rotation and Reference Systems Service adds a leap second every few years to keep the clocks we use to measure official time and the speed of Earth’s rotation in sync. The addition will mean that the last minute of June will have 61 seconds; while 23:59:59 usually becomes 00:00:00, the leap second will ensure the time becomes 23:59:60. How will you spend your extra second today? Check out this video by National Geographic for more information about the “leap second”!
A huge asteroid will pass closer to Earth than the moon Tuesday, giving scientists a rare chance for study without having to go through the time and expense of launching a probe, officials said.
Earth’s close encounter with Asteroid 2005 YU 55 will occur at 6:28 p.m. EST Tuesday, as the space rock sails about 201,000 miles from the planet.
“It is the first time since 1976 that an object of this size has passed this closely to the Earth. It gives us a great — and rare — chance to study a near-Earth object like this,” astronomer Scott Fisher, a program director with the National Science Foundation, said Thursday during a Web chat with reporters.
The orbit and position of the asteroid, which is about 1,312 feet in diameter, is well known, added senior research scientist Don Yeomans, with NASA’s Jet Propulsion Laboratory in Pasadena, California.
“There is no chance that this object will collide with the Earth or moon,” Yeomans said.
Thousands of amateur and professional astronomers are expected to track YU 55’s approach, which will be visible from the planet’s northern hemisphere. It will be too dim to be seen with the naked eye, however, and it will be moving too fast for viewing by the Hubble Space Telescope.
“The best time to observe it would be in the early evening on November 8 from the East Coast of the United States,” Yeomans said. “It is going to be very faint, even at its closest approach. You will need a decent-sized telescope to be able to actually see the object as it flies by.”
Scientists suspect YU 55 has been visiting Earth for thousands of years, but because gravitational tugs from the planets occasionally tweak its path, they cannot tell for sure how long the asteroid has been in its present orbit.
Track the asteroid, YU55, and track it’s journey as it passes by Earth on the NASA Asteroid & Comet Watch!
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