They are dwarf planets like Pluto. Kuiper Belt. The Latest. Several dwarf planets within the Kuiper Belt have moons. JPL's lucky peanuts are an unofficial tradition at big mission events. A spacecraft has sent back pictures of the sky from so far away that some stars appear to be in different positions than we'd see from Earth. The farthest object ever explored is slowly revealing its secrets, as scientists piece together the puzzles of the Kuiper Belt object NASA's New Horizons spacecraft flew past on New Year's Day, four billion miles from Earth.
A Prehistoric Puzzle in the Kuiper Belt. Meet the women leading two of humankind's two most distant space missions. Women at the Helm. The highest resolution images offer about feet 33 meters per pixel. New Horizons Flyby: Where to Watch. Closest approach takes place in the early morning hours of New Year's Day— a. EST—marking the most distant close exploration of worlds ever completed by humankind. Without Hubble's intriguing early images, there might have never been a mission to explore Pluto and the Kuiper Belt.
From its brightness and size, New Horizons team members have calculated Ultima's reflectivity, which is only about 10 percent, or about as dark as garden dirt. Beyond that, nothing else is known about it. With no apparent hazards in its way, NASA's New Horizons spacecraft has been given a "go" to stay on its optimal path as it speeds closer to a Jan.
Thirdly, we found that while the KBOs are very numerous, their combined mass is only a modest 0. This is so small that it would be difficult for the observed objects to have accreted, even over the age of the Solar System. The solution seems to be that the Kuiper Belt started out being much more massive than it is now, perhaps containing 20 or 30 Earth masses instead of 0.
Where did it go? The answer may lie in two other observational discoveries from the s. Many other resonances e. University of Arizona dynamicist Renu Malhotra gave us the answers. As the planet scooted outwards, it trapped some of the planetesimals beyond it into resonant orbits. In place of the old and rather boring clockwork Solar System in which the planets held their orbits and moved predictably for billions of years, we now recognise a much more chaotic and harder to follow history.
For example, simulations show that if radial migration caused two of the major planets to fall into a resonance of their own, this would have caused the entire architecture of the Solar System to be catastrophically upset. As a result of all this, the significance of the New Horizons encounter with Pluto has changed since the mission was first imagined in the late s.
Instead of visiting the last, most peculiar planet, we found that we had visited a large but otherwise unremarkable Kuiper Belt object. Even before New Horizons we knew a lot about Pluto, including its mass, diameter and density, the composition of its surface ices, the existence, nature and variability of its atmosphere and the properties of its satellite system.
But the New Horizons encounter has taken it to the next level by transforming Pluto from an astronomical object to a geological one, rich with surface detail that can never be detected from Earth. He became interested in astronomy after watching a spectacular meteor shower in his native Enfield.
Home Science What is the Kuiper Belt? A guide to the outer Solar System. Given their frequent trips into the inner solar system, most tend to exhaust their volatile ices fairly quickly and eventually become dormant, or dead, comets with little or no detectable activity.
Researchers have found that some near-Earth asteroids are actually burned-out comets, and most of them would have started out in the Kuiper Belt. The other source of comets is the Oort Cloud, where most long-period comets on highly tilted orbits originate. The Kuiper Belt is named for astronomer Gerard Kuiper, who published a scientific paper in that speculated about objects beyond Pluto. Kuiper's work didn't actually predict the populations of objects we observe in the region named for him, or crucially, their relationship with Neptune.
Neptune's orbit, not Pluto's, defines the belt's inner edge; and it's largely Neptune's gravity that has shaped the belt. But Kuiper and his ideas were well-known among astronomers such that the general idea of the belt came to be attributed to him. Pluto was the first Kuiper Belt object to be discovered, in , at a time before astronomers had reason to expect a large population of icy worlds beyond Neptune. At the time, scientists had not yet developed ideas about the outer solar system that suggested Pluto might have a lot of company.
So, despite its oddly elliptical and tilted orbit, it made sense at the time to think of Pluto as a lone planet. It would be another 62 years until the second KBO was found, in , finally leading to the recognition that Pluto is far from alone out there. But that spacecraft didn't visit any of the icy worlds in the region — none other than Pluto had been discovered yet. Voyager 2 visited Neptune's moon Triton in , and Cassini visited Saturn's moon Phoebe in — both could be worlds originally from the Kuiper Belt that have escaped.
The main part of the Kuiper Belt begins at Neptune's orbit. Credit: NASA. These four panels show the relative scale of clockwise from top left : The inner solar system, outer solar system, orbit of Sedna in the scattered disk, and the Oort Cloud. Artist's impression of the view from a KBO.
0コメント