This makes them up to 20 times bigger than those more familiar denizens of the deepest solar system, the comets.
Those periods, though, are measurable only because they are short enough for astronomers to have seen the comets in question more than once.
But the samples we collected from it we believe to be exactly the same materials that went into forming the comets and the solar system four and a half billion years ago.
The researchers say this dust must be coming from collisions among small bodies similar to the comets or icy bodies that make up today's Kuiper Belt objects in our solar system.
Long-period comets can arrive from any direction in space and are believed to originate in the Oort cloud (a reservoir of comets encircling the sun, the existence of which was worked out at the same time as the Kuiper belt by Jan Oort, a Dutch astronomer).
Subsequent missions will analyse the solar wind, three comets and the planet Mercury.
If the moon harbours ice, for example, measuring the amount of it at different depths could enable planetary scientists to work out the rate at which comets smashed into the lunar surface over its history, and that knowledge could then be plugged into models of the formation of the solar system.
Terry Moseley of the association said the dusty remains of comets which collide with the Earth at tremendous speeds can produce brilliant flashes almost as bright as the moon.
The data are the orbits of comets that are likely to have been first-time visitors to the inner solar system.
Data from NEAR could help answer questions about the origin and composition of asteroids, comets and the solar system, according to the mission managers at the Applied Physics Laboratory in Laurel, Maryland.
"This appears to be this comet's first-ever journey into the inner Solar System and it is expected to pass much closer to the Sun than most comets, " said Tony Farnham of the University of Maryland.
"The guess is that both the water and the dark material, which we think is organic-rich material, were delivered by the same objects impacting Mercury: some mixture of comets and the kinds of asteroids that are rich in organic and volatile material like water ice, " Prof Solomon said.
Lights might dim slowly from the edges or shapes will unexpectedly dart across the surface like comets.
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Some astronomers seemed to think that he and his colleagues had been too selective about the sample of comets they studied.
So the argument that some of the dots are comets depends on showing that there are more dots than chance should allow.
The new instrument is equipped with special filters which will enable astronomers to study regularly and in detail the ejection of several types of molecules by comets during their journey around the Sun.
The resultant tidal wobble, so the story goes, dislodges comets from their historical orbits and sends at least some of them tumbling towards the sun.
Added up over the whole sky, this suggested that the belt might contain a billion or more comets waiting to be unleashed on the inner solar system.
The problem is that for many large firms, systemic risk is a matter of exogenous events, sort of like comets which originate outside the normal operations of the solar system, suddenly appearing, flashing across the sky and then disappearing.
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But there is reason to believe that comets are what the Kuiper belt mostly consists of.
During this violent time, much of the debris would have resembled comets - dirty snowballs thought to be mostly slushy water surrounding a rocky core - slamming into Earth at velocities greater than 25 km per second (16 miles per second).
Two researchers (separated by the Atlantic ocean, rather than the English Channel), have used gravitational perturbations that affect comets, rather than planets, to predict the existence of something that might be a planet, or might be a star depending mainly on how you define a planet or a star.
After looking at the orbits of almost 300 long-period comets, they have concluded that too many are coming from particular parts of the sky.
The NASA Near Earth Objects (NEO) Program at the agency's headquarters in Washington, manages and funds the search, study, and monitoring of NEOs, or asteroids and comets, whose orbits periodically bring them close to the Earth.
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Large sun-grazing comets could bring on the sort of global electronics meltdown usually associated with electromagnetic pulse weapons or a full-scale nuclear exchange.
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This would make sense if short-period comets started off in the Kuiper belt and were nudged into closer orbits around the sun by the gravity of the most distant of the giant planets, Neptune.
Most financial talk treats systemic risk as a matter of exogenous events, sort of like comets that originate outside the normal operations of the solar system, unpredictably appearing, flashing across the sky and then suddenly disappearing.
Meteor showers are generated when Earth plows through streams of debris shed by comets on their path around the sun.
That would mean that any ice which has collected in those craters (perhaps from comets that have collided with the moon) would never evaporate.
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