New Horizons Spacecraft will travel back in time

[EntityX]

I was checking out an article about Pluto. I remember hearing how it was declassified as a planet a couple years back and wanted some more information. Here's the article. http://www.solarviews.com/eng/pluto.htm

In the article it says :

The New Horizons spacecraft was launched on January 16, 2006 and will make its closest approach to Pluto on July 14, 1015.

Here are some facts and/or quotes from the article:

From its time of discovery in 1930 to 2006 Pluto was considered to be the ninth planet in the solar system, but because additional objects have been discovered including Eris which is 27% more massive, the IAU reclassified Pluto and the other objects as dwarf planets.

Pluto's mass is approximately 0.0021 Earth mass, or a fifth of our moon.

Pluto's diameter is 2,274 kilometers (1413 miles) and Charon's diameter (Pluto's moon) is 1,172 kilometers (728 miles).

Pluto is usually farther from the Sun than any of the eight planets; however, due to the eccentricity of its orbit, it is closer than Neptune for 20 years out of its 249 year orbit. Pluto crossed Neptune's orbit January 21, 1979, made its closest approach September 5, 1989, and remained within the orbit of Neptune until February 11, 1999. This will not occur again until September 2226.

Pluto was officially labeled the ninth planet by the International Astronomical Union in 1930 and named for the Roman god of the underworld. It was the first and only planet to be discovered by an American, Clyde W. Tombaugh. It has since been reclassified as a Dwarf Planet along with Eris and Ceres.

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If Pluto was still considered a planet then we would now have at least 10 planets in our solar system since Eris is both more voluminous and massive than Pluto.

[EntityX]

Picture of Pluto and Pluto's moon Charon shown in comparison to size of US.

[wossname]

You'd think they would have picked pluto up on Air-traffic control radar if it was that close. Oh well.

[JPicasso]

Which one is the united states?

The smaller roundy thing?

[FunkyDexter]

...and the waiter asked, "How did you find your continent?"
and I said, "I just moved a couple planets aside and there it was."

[EntityX]

You guys are coming up with some good ones.

Back to the more serious side. Here's some more Pluto trivia from the article or links in the article:

Pluto's average distance from the Sun is 39.5 times Earth's average distance from the Sun and is 5.9 billion km.

Due to its great distance from the sun, Pluto's surface is believed to reach temperatures as low as -240°C (-400°F).

From Pluto's surface, the Sun appears as only a very bright star.

Pluto's icy surface is 98% nitrogen (N2). Methane (CH4) and traces of carbon monoxide (CO) are also present. The solid methane indicates that Pluto is colder than 70 Kelvin.

Eris, which is the only dwarf planet more massive than Pluto, is the most distant object ever seen in orbit around the Sun, even more distant than Sedna, the Kuiper Belt object discovered in 2003. It is almost 10 billion miles from the Sun and more than 3 times more distant than Pluto and takes more than twice as long to orbit the Sun as Pluto. It has an orbital period of 556.7 years.

[dclamp]

it is amazing that we know of objects that are a distance of 10 billion miles away...

[EntityX]

Here's the Eris link from the article on Pluto.
http://www.solarviews.com/eng/eris.htm

Aptly named, the icy dwarf planet, Eris, has rattled the general model of our solar system. The object was discovered on January 5, 2005 by Mike Brown, Chad Trujillo and David Rabinowitz at Palomar observatory in the out reaches of the Kuiper belt. The discovery came from images taken on October 21, 2003. It was announced on July 29, 2005.

Its detection provoked debate about Pluto's classification as a planet. Eris is slightly larger than Pluto.

So if Pluto qualified as a full-fledged planet, then Eris certainly should too. Astronomers attending the International Astronomical Union meeting in 2006 worked to settle this dilemma. In the end, we lost a planet rather than gaining one. Pluto was reclassified as a dwarf planet along with Eris and the asteroid Ceres, the most massive member of the asteroid belt.

If anyone ever lived on Eris it would be like living on a dwarf planet that had no sun because the Sun would be more like a star than a sun.

[visualAd]

it is amazing that we know of objects that are a distance of 10 billion miles away...

The furthest visible object with the naked eye is the Andromeda galaxy. Although it has a magnitude of only 3.4, it occupies about the same diameter in the night sky as the moon and the sun and is at a distance of over 2.5 million light years.

Gives a new meaning to the term long sighted.

[dclamp]

Gives a new meaning to the term long sighted.

you mean far sighted?

[visualAd]

you mean far sighted?

No, I mean long sighted.

[EntityX]

10 billion miles isn't that big a distance when you think on the cosmic scale. The dwarf planet Eris doesn't give off light like stars and galaxies do. It just reflects light from our Sun and our Sun is 10 billion miles away from it. So it's surprising that we were able to detect it. It's a dwarf planet that is lit up only with the light of a bright star. If I did my math correctly Eris is close to 14.9 light hours from the Sun. That's 62% of a light day. I calculate the Andromeda galaxy to be 1.47 billion times more distant from our Sun than Eris if it is around 2.5 million light years away. Eris is far from us in terms of planets in our own solar system but it's close in comparison to stars and galaxies. Like they say, it's all relative.

[BillGeek]

What REALLY gets me wondering is: How do they know that Pluto's surface is made of 98% Nitrogen, Methane, etc... if they've never even landed a probe there?

[mendhak]

Spectral analysis. And the smelloscope.

[Foxer]

What REALLY gets me wondering is: How do they know that Pluto's surface is made of 98% Nitrogen, Methane, etc... if they've never even landed a probe there?

http://en.wikipedia.org/wiki/Spectroscopy

Spectrometry is the spectroscopic technique used to assess the concentration or amount of a given species. In those cases, the instrument that performs such measurements is a spectrometer or spectrograph.

Spectroscopy/spectrometry is often used in physical and analytical chemistry for the identification of substances through the spectrum emitted from or absorbed by them.

Pretty clever huh.