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"The Unexplored Planet" --NASA's Fastest Spaceship on Approach to Pluto




One of the fastest spacecraft ever built -- NASA's New Horizons -- is hurtling through the void at nearly one million miles per day. Launched in 2006, it has been in flight longer than some missions last, and it is nearing its destination: Pluto.

“There is a real possibility that New Horizons will discover new moons and rings as well,” says Alan Stern, of the Southwest Research Institute and the mission’s principal investigator. Already, Pluto has five known moons: Charon, Styx, Nix, Kerberos, and Hydra. Numerical simulations show that meteoroids striking those satellites could send debris into orbit, forming a ring system that waxes and wanes over time in response to changes in bombardment. “We’re flying into the unknown,” says Stern, “and there is no telling what we might find. The encounter begins next January,” adds Stern. “We’re less than a year away.”

Other than a few indistinct markings seen from afar by Hubble, Pluto’s landscape is totally unexplored. Although some astronomers call Pluto a “dwarf” planet, Stern says there’s nothing small about it. “If you drove a car around the equator of Pluto, the odometer would rack up almost 5,000 miles—as far as from Manhattan to Moscow.” Such a traveler might encounter icy geysers, craters, clouds, mountain ranges, rilles and valleys, alongside alien landforms no one has ever imagined.

Closest approach is scheduled for July 2015 when New Horizons flies only 10,000 km from Pluto, but the spacecraft will be busy long before that date. The first step, in January 2015, is an intensive campaign of photography by the Long Range Reconnaissance Imager or “LORRI.” This will help mission controllers pinpoint Pluto's location, which is uncertain by a few thousand kilometers.

"LORRI will photograph the planet against known background star fields," explains Stern. "We’ll use the images to refine Pluto’s distance from the spacecraft, and then fire the engines to make any necessary corrections.”
At first, Pluto and its large moon Charon will be little more than distant pinpricks—“a couple of fat pixels,” says Stern--but soon they will swell into full-fledged worlds.

By late April 2015, the approaching spacecraft will be taking pictures of Pluto that surpass the best images from Hubble. By closest approach in July 2015, a whole new world will open up to the spacecraft’s cameras. If New Horizons flew over Earth at the same altitude, it could see individual buildings and their shapes. The image above NASA space-artist Ron Miller's concept of geysers and sundogs on Pluto.

“Humankind hasn't had an experience like this--an encounter with a new planet--in a long time,” he says. “Everything we see on Pluto will be a revelation.”

He likens New Horizons to Mariner 4, which flew past Mars in July 1965. At the time, many people on Earth, even some scientists, thought the Red Planet was a relatively gentle world, with water and vegetation friendly to life. Instead, Mariner 4 revealed a desiccated wasteland of haunting beauty. New Horizons’ flyby of Pluto will occur almost exactly 50 years after Mariner 4’s flyby of Mars—and it could shock observers just as much.

Although temperatures on Pluto's surface hover around -230 °C, but researchers have long wondered whether the dwarf planet might boast enough internal heat to sustain a liquid ocean under its icy exterior.

Guillaume Robuchon and Francis Nimmo at the University of California, Santa Cruz, have calculated that the presence of an ocean depends on two things: the amount of radioactive potassium in Pluto's rocky core, and the temperature of the ice that covers it.

Density measurements suggest a rocky core fills 40 per cent of the dwarf planet's volume. If the core contains potassium at a concentration of 75 parts per billion, its decay could produce enough heat to melt some of the overlying ice, which is made of a mixture of nitrogen and water.

It should have at least that much potassium and probably more, says William McKinnon at Washington University in St Louis, Missouri, who points out that Earth, which probably formed with less of the volatile element due to its closer distance to the sun, has 10 times that concentration in its core.

Heat from Pluto's core will trigger convection in the surrounding ice, and if the ice churns too quickly, the heat will simply escape into space before it can do much melting. If it flows substantially more slowly than Antarctic glaciers on Earth, however, then the top 165 kilometres of ice could provide enough insulation for a liquid ocean of the same depth to exist below, the team concluded.

The viscosity of the ice depends on the size of individual ice particles, with smaller grains flowing more easily. There is no way to measure this from Earth, but Pluto's shape could reveal evidence of an ocean, the team says. Pluto's spin is slowing down due to tugs from its large moon Charon. Fast-spinning objects bulge out at their equator, but a soft interior would allow the world to relax into more of a sphere as its spin slows down. NASA's New Horizons probe will image the dwarf planet's shape when it flies past in 2015.

"It's very exciting to think that these dwarf planets could have astrobiological potential," says Stern.

The Daily Galaxy via Science@NASA




To the Daily Galaxy

Keep up with what`s going on elsewhere as far as Solar System observations.Our website SPACENOW.COM.BR has already seen Pluto and Charon.The images are available at that URL, and the IAU knows about it.
Pluto has a gigantic mountain that measures close to 500km in height and Charon is a world still not formed.Youcan check it all out at the web address mentioned in this comment.

Thank you for accurately referring to Pluto as a planet, which it is. If Pluto does have a subsurface ocean, what are the chances of that ocean harboring microbial life?

soon some low "scientist" will disqualify Earth as a planet cause it`s too small compared to most planets in Milky Way. Thanks God nobody will remember his name as well.

The status of Pluto has been decided by scientific criteria proposed and accepted through argumentation and evaluation of all the "available" data and was done so in a public forum. Within that environment of open debate by professionals, Pluto was redefined as a demi-planet. New discoveries require new thinking to sort out all the major and minor celestial objects we have and will encounter in the Universe as our tools and understanding progress. Short version: "Cease the hate and catch the wave." For those who feel that Pluto has been misdefined, the current mission to Pluto should provide you with fresh data to support or reject your professional "scientific" arguments.

I respect the work that went into New Horizons but the comment about Pluto's size was silly.

“If you drove a car around the equator of Pluto, the odometer would rack up almost 5,000 miles—as far as from Manhattan to Moscow.”

Is that supposed to be inspiring, given that Earth is 24,000 miles in circumference, and our own Moon is about the size of Pluto? It was de-classified for a good reason. Being defensive about it doesn't increase support for the mission--you had me at "1 million miles per day". Just tell it like it is, don't try to hype Pluto for crying out loud.

Agree with Gogore. The IAU semantic players are nobodies.

This will be exciting! The Kuiper Belt objects are so intriguing! Who knows how many other astounding objects exists out there? I'm so glad we get to study one up-close!

Black SciFi, No, the status of Pluto has not been decided and accepted by the scientific community. One subgroup of that community, 424 people, or four percent of the IAU, adopted a very problematic resolution on the last day of a two-week conference in violation of the IAU's own bylaws. They did this after rejecting the resolution proposed by the IAU's own committee and then throwing together a different resolution, one crafted deliberately to exclude Pluto, which they put to the General Assembly floor without first vetting it by the appropriate committee. An equal number--several hundred--professional astronomers signed a formal petition rejecting the IAU decision. That petition was led by none other than Dr. Alan Stern, Principal Investigator of New Horizons.

The debate process was not open; it was directed by one group who specifically had an agenda to exclude Pluto. Three years later, a group of professional astronomers petitioned the IAU to reopen the discussion, and the IAU leadership refused. The current mission will support, not refute, the fact that Pluto is a full-fledged planet, not a demi-planet. Meanwhile, there is no reason to accept an attempt to impose one interpretation in an ongoing debate because this group of 424 people voted on it. Science is not determined by decrees from "on high."

The time is almost here when New Horizon will reach Pluto, and the images it will capture will most likely capture the hearts and minds of the many. An history event nine years in the making for April of next year will be a glorious day indeed.

I had once read the classification of planets in the opinion of the 424. There is no good news for more planests that way : Pluto is circling a star just like Earth, but how do you define a star? How big must it be and how much "ignited" ? A brown dwarf qualifies ? Because they tend to be more like Jupiter than like a bright star. Another thing is the size of a planet but that means Mercury will be banned too , it`s too small. Even Mars is not big enough. Another criteria :debries around the planet or same orbit : we now know there are milions of asteroids on the same orbit as Earth, some waiting to hit us again. And i mean big ones, much bigger than the one that extinted dinosaurs. So in teh end all is just about semantics or grammar. Noone needs their criteria.

These 2 articles by Brazilian Media Conglomerate O GLOBO (Our Brazilian equivalent to your AOL/Time-life)herald the discoveries of SPACENOW (giant montain on Pluto and geologicaly Hyper-active moon ,Charon)made with our breakthrough HMIR technique!

Perhaps the IAU's criteria for a celestial object being defined as a planet should be revisited by those who object to their conclusions.

I look forward to the debate being driven by the science collected by New Horizins once it arives at Pluto. I would add that the old definition would have added several more KBO's to the family of planets in our solar system. To wit, an asteroid can be defined as a rock, but a rock cannot be defined as an asteroid without additional criteria.

the fastest space ship ever and it is still only doing about 60% of the earths speed. maybe some one can explain to me why, if we send a ship into space in the direction of our (earth) travel, we can not attain the speed of earth plus?

John Burns, you have to remember that it's fighting the gravity well of the Sun. That alone would slow it some.

What is wrong with adding several more KBOs to our Sun's family of planets? The idea that our solar system cannot have "too many planets" has no scientific basis.

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