Pluto No Longer A Planet

[DizzyGuy]

I think that they did, it was something that I heard... but I've been so busy lately that I haven't had time to find the sources... sorry, I might be wrong

[Sonthert]

So, here's what's new in the area of dwarf planets and TNOs (Trans Neptunian Objects)

The Dawn Spacecraft was launched in September 2007 to visit 4-Vesta (2010) and 1-Ceres (2015) in the Asteroid Belt. Some optimistic people have offered that the previously uninteresting C-type asteroid 1-Ceres might have conditions that could foster life. They have begun to observe water-ice under a dusty surface. It may have a weak atmosphere, it gets up to a chilly -40C in its closest approach to the Sun, but what actually lies on the surface will be hopefully discovered by Dawn (The Spacecraft). Dawn is the first spacecraft to land on a target and then leave for another target. All other multiple target craft have flown by. a C-Type asteroid, is mostly rocky and boring, like the Moon.

4-Vesta, probably boring, is more metallic, but sports presumably evidence of a large impact some 4.4 GY ago. We'll begin to hear more about this at the end of next year or the beginning of 2011.

In 2008, a new term "Plutoid" was coined for small bodies that lie satisfactorily far enough from Neptune so that their orbits were stable.

Pluto, now apparently sports three moons (or Pluto-Charon sports two moons, depending on your opinion). Nix and Hydra were discovered in late 2005. Pluto resembles Triton (Neptune's moon) greatly, having mostly frozen nitrogen for a surface. As Pluto moves through perhelion, it develops a thin atmosphere of gaseous nitrogen, vaporizing from the frozen surface. Pluto is moving away from it perhelion, getting colder, even as you are reading this. Planetary data from its surface shows distinct features. Pluto is colder than it should be, from the opposite of the greenhouse effect, cooling caused by the vaporization of solids (or the melting of solids in warmer areas, like the Earth). Charon, on the other hand, see to have more water and ammonia ice on it as it hangs perpetually motionless in the Plutonian skies, face locked to Pluto, matching Pluto's movements perfectly. Charon's surface is likely to be more than 50% water. Nix and Hydra are quite recent in their discovery, but ironically could be the biggest obstacles to the New Horizons Probe, launched almost at the same time they were discovered. Scientists reason that Pluto may have a dusty shroud that may damage New Horizons before it can make contact with Pluto. It was previously thought there was nothing orbiting beyond Charon. If Nix and Hydra are shattered remnants of a collision, there could be lots of dust and tiny rocks that could damage or disable New Horizons. Or alternately, their light gravity could be dragging junk in from the rest of the Kuiper Belt. Last heard, New Horizons had slingshot away from Jupiter (2007) and New Horizons should make Pluto's orbit around 2015...same general time period as when Dawn meets 1-Ceres.

Two minor planets have been officially named, the Plutoids Makemake and Haumea (Named for Hawaiian gods, perhaps????) Makemake has no discovered satellites (which is unusual) and it is probably comprised of a rocky core with principally methane on the surface. Nitrogen, being more volatile at these temperatures and pressures, has probably long since escaped the small minor planet (Third largest, behind Eris (#1)and Pluto (#2)). It is the second brightest trans-Neptunian Object, behind Pluto. Its widely tilted Cubewano orbit made it difficult to discover. Eris, although much larger, is farther away and dimmer. Haumea is smaller than Makemake, but has two small satellites and is twice as long as it is wide (Visualize some god's throwing his football on a roof and leaving it there for several billion years...thats what Haumea looks like). It is also a Cubewano, or it was. Somehow it has been delisted, but has not been relisted as anything...which is quizzical. A Cubewano is a Plutoid, its orbit is independent of Neptune, it exhibits no resonance with Neptune's orbit. These planets had silly astronomical names like 2003 EL-55, or things like that...now they have real (!) names. All the planets in the Solar System, if residing outside the sphere of Neptune would be considered cubewanos...orbiting the Sun, that is, would make a body a cubewano, if its beyond Neptune.

Orcus, has one moon and is a Plutino (as opposed to a plutoid), with a 3:2 resonance to Neptune, the same as Pluto. Its orbit is about the same as Pluto's in shape, but tilted backwards in relation to Pluto. It also seems to be opposite Pluto in other ways, as Pluto speeds away from its perihelion with the Sun, Orcus is chugging along towards its aphelion. Most of the discovered minor planets ARE in perihelion...because they are easier to see when they are closer to the Sun (and us)...and we haven't had the ability to see as far as we can now. Orcus is the exception. Orcus probably has frozen water, ammonia, methane, some nitrogen and ethane on its surface, but resembles Charon more than it does Kuiper Belt Sludge, like Pluto and Triton. Scientists don't exactly know what makes up about 25% of Orcus' surface, but it is obviously ice and scientists continue their exploration.

Quaoar, a cubewano, is beyond Pluto, but its orbit is nearly circular. It has actual water crystal on its surface, similar to Charon and Haumea...which is likely explained by cryo-volcanism (some people propose meteor impacts...but it is less likely) or some sort of cold eruptions of relatively warmer materials, similar to the volcanism of the Earth, but they can be solids, too. It might be caused by nuclear decay or the unknown influence of a large body yet undiscovered (Sedna's orbit implies there could be an undiscovered large body far, far away from the Sun). Quaoar, similar to Haumea, is football shaped very likely, but not as dramatically as Haumea.

Varuna, the 9th largest non-planet in the Solar System (Eris, Pluto, Makemake, Haumea, 1-Ceres, Sedna, Orcus, Quaoar being larger, in order) has still very little know about it. Its small size makes its relatively close cubewano orbit rather worthless for gathering information. An occult (where a planet passes in front of a star) with a star in Gemini in 2008 was supposed to hammer its size down, but the data has yet to be reviewed and determined. Hopefully in the next few months, we'll find out how big Varuna actually is.

Sedna, my personal favorite of the TNOs, Sedna (2003-VB-12) has passed its perhelion of 76 AU and is making its way slowly to the Oort Cloud, where nothing is happening quickly or in warmth. Sedna is still well within the normal bounds of our solar system, plodding its way through its 12,000 Year orbit (Pluto orbits in about 250 Years, Neptune in 185 Years). Recently, Sedna's surface, although reddened by tholins (Methane-ice crystals formed in extreme cold in near vacuum) is believed to be quite similar to Triton and Pluto "Kuiper-Belt Sludge" Methane, methanol, tholin and various carbon crystals. Triton is not red because if the pressure that Neptune places on it, forming giant (8Km, 4.8Mi) geysers that are reshaping the surface continually. Sedna is a detached object, being one of nine members of a very distant group of objects that orbit around the Sun in the most informal sense of the word. Properly, they orbit in a fashion that has been sculpted by objects that DO orbit the Sun, making the orbit appear to orbit the sun. Scattered disk objects are scattered by Neptune, Kuiper Belt objects are influenced by Neptune, and detached objects don't have any influence with Neptune. Detached objects tend to have large, elliptical objects and dance around short of the Oort cloud (the outer boundary of the Solar System), but well beyond the comfort of the Kuiper Belt, the second belt of bodies in the Solar System. Some detached objects are surmised to have unusual resonances of 4:1, 5:1, 8:3, 10:3 or even 20:1 with Neptune, making them scattered disk objects. The distinction is weak and these objects live a long, long, long way from the Sun. Most of them getting closest to the Sun at distances of 40 or more times the distance from the Earth to the Sun (1 AU is defined as the distance from the Earth to the Sun...some coincidence...huh?). Pluto gets closest to the Sun at a about 30 A.U. and swings out to about 50 A.U.. Most of these little rocks swing from about 40AU to 90 AU, but can stretch out to 90 AU (perihelion) and 500 AU (aphelion). Sedna, on the other hand, has a aphelion at around 950 A.U.. It is even conjectured that Sedna may be an illegal alien, having been ripped from a passing small star when it passed too close to our Sun. Its also thought that Sedna's orbit could could portend an Earth-Sized object somewhere around 1500 A.U. from the Sun, a Neptune-Sized object at around 2500 A.U. from the Sun or even a dark, cold Jupiter-sized object around 5500 A.U. from the Sun. Proxima Centauri, the 2nd closest star to the Earth (The Sun being #1) is approximately 65,000 A.U. from our Sun.

Well, that's about it, the update for substantial sized bodies outside of the Eight Planets of the Solar System.

[coastlines]

Even though I read all of it, I am still impressed that you typed all of that out.

[Sonthert]

Aw shucks, you're sweet.

I'm glad somebody read it. It was pretty late, and I was just trying to get through it...

COROT is a European mission to look for extra-solar planets. It is online as of February of this year.

Integral is a project to find out if faint gamma ray bursts occur or not. Gamma ray bursts are massive, destructive beacons of residual energy, likely from supernovae explosions. Powerful ones are obvious, the question is "are their faint ones? If not...why?" and Integral found that there are.

NASA/JPL are continuing their development of the next generation of space vehicles, Ares Launch vehicles, Orion Crew Vehicles and Altair Extra-Vehicular Landers are part of the Constellation Program. These modular units are designed to be much more flexible and reusable than previous NASA craft, more along the lines of the Space Shuttle, but including Space Station and transportation units.

Kepler is a spacecraft looking at hundreds of thousands of stars simultaneously, looking for planets as small as the Earth. On June 15, it had a failure and has been since restored and is transmitting data again.

LCROSS is looking to see if there's water ice hiding in the crater on the southern polar crater of the moon. These craters are permanently in shadow and it is conjectured that ice deposited by passing comets could reside there indefinitely.

An update on Dawn: her ion propulsion system successfully came back online and is well on track to make landfall with 4-Vesta in 2010-2011. The ion propulsion system is quite fascinating, really, it uses Xenon and solar energy to ionize the Xenon and produce power. Dawn is past the orbit of Mars and is about halfway to Vesta. Vesta lies on the nearest side of the Asteroid belt to the Earth. 1-Ceres lies on the side of the asteroid belt furthest from the Earth.

IBEX is collecting high speed particles to determine the interactions of our solar system with the interstellar medium.

There are five craft exploring Mars currently, some are looking for water there, some are looking for water that was once there, some are just roaming around (Opportunity and Spirit) looking for anything interesting. The last one is examining Mars for interesting minerals from orbit.

Trivia question: Of the 8 planets, which is the only one that is not completely mapped? If you said Pluto, you haven't read this thread at all (although you aren't wrong. ). Its Mercury. Prior to the launching of MESSENGER, Mercury had approximately 40% of its surface unmapped. Why? Mercury is face locked to the Sun, much like the same side of the moon faces the Earth, the side closest to the sun is only facing us when the Sun is in the way. Lacking spectacular sunglasses, seeing anything in terms of surface detail is impossible. MESSENGER was sent to go lurk around and map Mercury. MESSENGER is slated to fly-by Mercury in September, 2009. It has already confirmed some very strange results, Mercury has an active magnetic field, a north and south pole, like the Earth, and unlike the Earth it has magnetic "tornadoes" that strip metallic ions from its surface, forming a strange, tenuous atmosphere of metal vapor. It may be volcanically active, evidence of volcanoes around the massive Caloris Basin have been found, but most scientists are skeptical about active volcanism on Mercury (although cryo-volcanism is observed on several satellites in the Solar System, including Triton). Mercury also seems to be shrinking...a lot.

Pioneer 10 and 11...inactive you say? Dead power systems, you say? You're right, but some interesting phenomena popped up in Pioneer 10 and 11's trajectories. For some reason, spacecraft sent out magically move their trajectories. Pioneer 10 and 11 were the first to exhibit this magical transit. Nobody knows why. Some scientists have theorized that it is due to unseen dark matter in our Solar System. I think that if the data is correlated, we will find the ancestral home of the Charcoal Gnomes. If you want more non-gnome related material, look it up, its quite interesting. Pioneer may be tell us more about the Solar System than we dreamed of or planned on, even though they can't talk to us anymore. Some scientists are saying that these results actually disprove the existence of dark matter and bespeak of a force that explains why the universe seems to be "speeding up" in its expansion.

The Pioneer Anomaly

Related is the fly-by phenomena:

Flyby Anomaly

There are two craft reconnoitering around Venus. They also found metallic components in Venus' atmosphere.

Well, thats all that seems really cool, NASA also has two dozen spacecraft looking at the Earth, but jeez! Reruns?