Pluto no longer a planet

[Sarxis]

So it is classified as a 'dwarf planet' now. That isn't news, or really even changing what we have been calling it - that Pluto is a small planet.

According to the IAU's definition a planet is: "The IAU members gathered at the 2006 General Assembly agreed that a "planet" is defined as a celestial body that (a) is in orbit around the Sun, (b) has sufficient mass for its self-gravity to overcome rigid body forces so that it assumes a hydrostatic equilibrium (nearly round) shape, and (c) has cleared the neighbourhood around its orbit."

Has cleared the neighbourhood around its orbit? In what way? And have any of the planets even done this? This last defining point assumes a lot, and may not hold true to what many might call a 'planet' even if there remains a great deal of space debris in the immediate vicinity or along the orbital path of such.

I can forsee this definition being modified again in the future, especially once better glimpses of distant star systems begin to occur.

[Will9]

Originally posted by MichaeltheGreat


That would kill off Mercury.

Yes, plus mercury hasn't cleared the sun out of it's neighborhood.

[chequita guevara]

[Q]Originally posted by MichaeltheGreat

That would kill off Mercury.[/QUOTE]

Wiki, on Mercury's atmosphere.

Mercury is much too small for its gravity to retain any significant atmosphere over long periods of time, but it does have a very tenuous atmosphere containing hydrogen, helium, oxygen, sodium, calcium and potassium. The atmosphere is not stable—atoms are continuously lost and replenished, from a variety of sources. The hydrogen and helium atoms probably come from the solar wind, diffusing into Mercury's magnetosphere before later escaping back into space. Radioactive decay of elements within Mercury's crust is another source of helium, as well as sodium and potassium. Water vapor is probably also present, being brought to Mercury by comets impacting on its surface.[11]

[Ben Kenobi]

Ceres is an asteroid and always has been.

Hardly. The original definition of 'planet' was merely 'wandering star', by which could be observed by the eye and their motion among the heavens was different from the background.

Now that we know about proper motion and all, this definition doesn't really work any more.

Ceres was discovered by accident. Piazzi was searching for a star listed by Francis Wollaston as Mayer 87 because it was not in Mayer's zodiacal catalogue in the position given. Instead, Piazzi found a moving star-like object, which he thought at first was a comet.

Piazzi observed Ceres a total of 24 times, the final time on February 11, when illness interrupted. On January 24, 1801, Piazzi announced his discovery in letters to fellow astronomers, among them his fellow countryman, Barnaba Oriani of Milan. He reported it as a comet but "since its movement is so slow and rather uniform, it has occurred to me several times that it might be something better than a comet".[8] By early February Ceres was lost as it receded behind the Sun. In April, Piazzi sent his complete observations to Oriani, Bode, and Lalande in Paris. They were shortly thereafter published in the September, 1801 issue of the Monatliche Correspondenz.

To recover the asteroid, Carl Friedrich Gauss, then only 24 years old, developed a method of orbit determination from three observations. In only a few weeks, he predicted the path of Ceres, and sent his results to Franz Xaver, Baron von Zach, the editor of the Monatliche Correspondenz. On December 31, 1801, von Zach and Heinrich W. M. Olbers unambiguously confirmed the recovery of Ceres.

Status

Johann Elert Bode believed Ceres to be the "missing planet" that Johann Daniel Titius had proposed to exist between Mars and Jupiter, at a distance of 419 million km (2.8 AU) from the Sun. Ceres was assigned a planetary symbol, and remained listed as a planet in astronomy books and tables (along with 2 Pallas, 3 Juno and 4 Vesta) for about half a century until further asteroids were discovered. Ceres turned out to be disappointingly small for a planet, showing no discernible disc, so Sir William Herschel coined the term "asteroid" ("star-like") to describe it.

http://en.wikipedia.org/wiki/1_Ceres

[LordShiva]

Gauss was such a ****ing badass!

[Winston]

Heh!

[Geronimo]

Originally posted by LordShiva

is it usual to sign demands you that write out in cut out letters?

[Heresson]

Originally posted by Brachy-Pride
just saw this in comments , lol

geek humor


"you are fired!" "b*itch!"

But imagine the 11 planets proposition was passed.... Imagine a new girl calling " in the name of UB313!!!"

[Colonâ„¢]

[chequita guevara]

How big is Sava's ego?

[self biased]

still dwarfed by pekka's.

[Colonâ„¢]

My ego is earth's, because that's the prettiest one of them all.

[Guynemer]

Originally posted by chegitz guevara
How big is Sava's ego?

Antares is invisible at this scale.

[General Ludd]

Antares is pretty big.

[LordShiva]

Originally posted by Geronimo
is it usual to sign demands you that write out in cut out letters?

Erm... Yes.