The fastest man-made object ever built, the half-ton NASA New Horizons spacecraft, crosses the orbit of Uranus today on its nearly decade-long odyssey to the dwarf planet Pluto.
The probe is now 1.8 billion miles from Earth, but still has nearly 1.2 billion miles to go before encountering Pluto. To underscore the enormity of that distance, it now takes a radio signal 2.5 hours to travel back to Earth from the spacecraft.
The nuclear-powered craft is hurtling though the interplanetary void at 35,000 miles per hour. That's fast enough to escape the solar system forever and join the ranks as one of our earliest starships (albeit poking along so slowly it will take 80,000 years to reach the distance of the nearest star).
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If you were traveling along with the probe today, you'd look back and see the sun at a small spot of light that is only 1/400th as bright as seen from Earth.
At this distance Earth is almost lost in the sun's glare. Jupiter and Saturn flank the sun at two brilliant diamonds at nearly their greatest western and eastern elongation, respectively. Even beyond the halfway point, the ultimate destination, Pluto, still cannot be seen with the naked eye.
Like a science fiction space traveler, the probe's computers and electronics are in hibernation for about 90 percent of the long journey. The spacecraft will be awaken from its current sleep on May 9 for its fifth checkout (since launch) that involves testing of all the onboard instruments to see if they are still healthy.