backtop


Print 58 comment(s) - last by Wolfpup.. on May 15 at 10:13 AM

NASA's first ion probe studies planetoid; will go on to study Ceres dwarf planet, which may have a hidden ocean

Located in our solar system's asteroid belt, mid-way between Mars and Jupiter, there's an area where the dense field of asteroids grows sparse.  Orbitting in this region, known as the Kirkwood gap is a massive planetoid -- 4 Vesta.

I. Ion-Propelled Probe Produces Results

Named after the Roman goddess of home and hearth, Vesta is the second largest object in the asteroid belt, dwarfed in size only by ice-rock dwarf planet Ceres.  Vesta is slightly closer to Earth than Ceres.

The fuzzy mega-asteroid (also referred to as a planetoid) was just a mysterious fuzzy spec in astronomers' telescopes until July 2011, when the U.S. National Aeronautics and Space Administration's Dawn probe entered orbit.  Launched in Sept. 2007, Dawn is a very special probe, in that it is the first pure exploratory probe to use ion propulsion.

Dawn probe
[Image Source: NASA/JPL-Caltech/UCLA/McREL]

Now NASA's findings have been published in the prestigious peer-reviewed Science journal.

Ceres Hubble v. Dawn
Ceres -- left (Dawn photos); right (Hubble) [Image Source: NASA]

Using the size, shape, and gravitational field of the asteroid, the research team was able to estimate that the asteroid had a 220km (135 mi.) diameter metal core, much like a miniature version of the metal core found in the Earth and other planets.

Armed with this information the team has proposed a bold hypothesis -- that Vesta is one of the solar system's only surviving protoplanetoids.  The proto-planetoids formed approximately 2 million years after solids began to coalesce throughout the solar system into planets and smaller bodies.  

Vesta
Vesta is the second largest object in the asteroid belt. [Image Source: NASA]

These smaller sisters to full planets like the Earth and Mars had a similar structure, with dense elements like iron sinking to the core, and lighter elements like carbon, oxygen, and silicon, rising to the surface.  But as they had much less mass, their larger siblings -- the solar system's nine planets (or 10, if you count Eris and Pluto) devoured all but a handful of these smaller bodies.

II. Vesta: Portrait of a Survivor

But Vesta survived.

That's not to say that parts of Vesta didn't wind up getting incorporated into the Earth and Mars.  Life in the asteroid belt is full of collisions, and much material is upheaved from the surface of Vesta and sent hurling across the solar system.

Scientists have pinpointed Vesta's handouts to a special type of meteorite -- howardite-eucrite-diogenite (HED) -- which account for approximately 6 percent of the total meteorites that collide with Earth yearly.  Their source was confirmed by spectroscopy, which revealed Vesta's surface to be rich in iron and magnesium core components of the meteorites.

Vesta HED Meteors
Vesta is an apparent source of the abundant HED meteors [Image Source: Univ. of Tennessee]

The precise ratio of these elements, seen seldom else in the solar system -- except on Vesta's surface and the HED meteorites, leaves little doubt than many or all of them come from the planetoid.

The Dawn probe indicates that many of those debris may come from a pair of large collisions that left two gaping craters in the planet's southern bottom.  One of these impact craters, named Rhea Silvia, is 427 km (265 mi.) across.

Dr. David O'Brien, from the Planetary Science Institute in Tucson, Ariz. and a participant in the study, told BBC News, "Our estimate [is that] about 250,000 cubic miles [were] excavated from Rhea Silvia.  To put this into another perspective - 250,000 cubic miles is enough to fill the Grand Canyon a thousand times over."

III. Next Stop -- Ceres

The probe's exploration of Vesta is currently wrapping up.  Its last major objective for this leg of its misison will be to collect images of the planetoid's northern pole, which is currently clothed in season darkness.  With that complete, researchers should have the celestial body's surface fully mapped out.

The probe will then fire up its ion engines and cruise farther out in the belt, entering the orbit of Ceres.  That phase of the expedition is to head towards Ceres, the inner solar system's only dwarf planet.  Rich in carbon and water, the planetoid may hold a liquid ocean under its icy surface.  Where there's carbon and liquid water on Earth there is life, so expect intrigue to be high when Dawn examines Ceres for signs of liquid water.

Sources: NASA, Science, BBC News



Comments     Threshold


This article is over a month old, voting and posting comments is disabled

How many planets?
By Trisped on 5/11/2012 5:04:34 PM , Rating: 3
quote:
nine planets (or 10, if you count Pluto)


I count 8 planets, 9 if you count Pluto. Or is the Sun a planet now?




RE: How many planets?
By e36Jeff on 5/11/2012 10:47:12 PM , Rating: 5
Its 10 because if Pluto is a planet so is Eris. Eris is a dwarf planet that is slightly larger in volume and much larger in mass than Pluto. Its located a bit more than 20 AU farther out than Pluto in the Scattered disc, which is the region of space beyond the Kuiper belt.


RE: How many planets?
By DBCooper71 on 5/12/2012 1:02:07 AM , Rating: 3
No, in that case it would be: "eight planets (or 10, if you count Pluto and Eris)"


RE: How many planets?
By CZroe on 5/14/2012 3:12:26 PM , Rating: 2
They think they corrected it with your suggestion, but it's STILL wrong!

"the solar system's nine planets (or 10, if you count Eris and Pluto) devoured all but a handful of these smaller bodies."

Bwa ha ha! 1=2


RE: How many planets?
By ganjha on 5/12/2012 10:07:06 AM , Rating: 3
There are eight planets; Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, and Neptune. Then there are five dwarf planets or planetoids; Ceres, Pluto, Haumea, Makemake, and Eris.

So eight or thirteen, as far as we know today.


RE: How many planets?
By AssBall on 5/12/2012 3:39:43 PM , Rating: 1
Hell if your going to count Pluto you may as well count Charon.


RE: How many planets?
By ganjha on 5/13/2012 5:05:59 AM , Rating: 1
Charon orbits Pluto and therefore cannot be classified as a planet or planetoid. Planets must orbit the sun.


RE: How many planets?
By Nexos on 5/13/2012 12:09:34 PM , Rating: 4
Technically, since the barycenter of the Pluto-Charon system lies outside of plutos mass, both Pluto and charon should be counted as parts of a binary dwarf planet system, not as a planet and a moon.


RE: How many planets?
By ganjha on 5/14/2012 4:53:33 AM , Rating: 2
Send a letter to the IAU with your recomandation.


RE: How many planets?
By gamerk2 on 5/14/12, Rating: 0
RE: How many planets?
By Wolfpup on 5/15/2012 10:13:12 AM , Rating: 2
I've heard some VERY convincing stuff from astronomers on why the "dwarf planet" classification is nonsensical and embarrassing...

But actually even the "if it doesn't directly orbit a star it's not a planet" thing doesn't make much sense, for obvious reasons.


RE: How many planets?
By Schadenfroh on 5/12/2012 12:06:32 AM , Rating: 4
Obviously, you have never watched the historical annals of The Doctor:

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


RE: How many planets?
By stardude692001 on 5/12/2012 5:43:27 AM , Rating: 2
IF they were talking about the very early solar system they might have included the mars sized body that might have collided with the earth to give us our moon. but if you are going that far back there is no way to know if there weren't more than impacted with other planets like Uranus or were ejected from the solar system entirely.


RE: How many planets?
By DanNeely on 5/12/2012 11:47:48 AM , Rating: 2
Once you start doing that you end up with a bunch of other hypotheticals. Tipping it over without screwing up the moon system required Uranus to have taken at least two hits from planetary sized objects; and modelers can't get the orbits of the outer planets to work unless Jupiter expelled at least one planet from the solar system entirely.


RE: How many planets?
By JKflipflop98 on 5/12/2012 5:39:12 PM , Rating: 2
I've seen physics simulations of accretion disc formation and occasionally if there's turbulence towards the outer ~70% of the disc you sometimes get a localized "whirlpool" of flow in the N-S direction.

Since our early solar system was just as such, I've always imagined that's the reason why our own cheeky gas giant spins the way it does.


Pluto
By faster on 5/11/2012 10:32:29 PM , Rating: 1
Although Pluto is a dwarf planet, and only the second largest in our system, I have always been in favor of granting it honorary planet status.

Having been taught all through school that it was a planet, my sense of anthropomorphized empathy drives me to support planethood for Pluto. I figure why not? We run commercials on the radio selling the rights to name some star in the universe after your mother for Mother’s Day. We control the naming rights on the universe as far as our eye can see, and even farther, right?

Or do we have to keep it classified a dwarf planet because we don’t want to look stupid when we meet the other aliens? I can see that point, but the aliens might understand our preferential treatment of Pluto because of it’s proximity to our planet, right?




RE: Pluto
By DBCooper71 on 5/12/2012 1:23:03 AM , Rating: 5
I'm afraid that when we meet the aliens we're going to look stupid no matter what


RE: Pluto
By Solandri on 5/12/2012 3:50:16 PM , Rating: 3
quote:
We run commercials on the radio selling the rights to name some star in the universe after your mother for Mother’s Day. We control the naming rights on the universe as far as our eye can see, and even farther, right?

Those radio ads are a scam. The companies running them have no authority to name anything other than their pets and kids. You are basically paying them $50 to print your name in their book. That's it.
http://en.wikipedia.org/wiki/Astronomical_naming_c...

The IAU is the only authority widely accepted to give names to stars, and they do not sell naming rights. You have to be the discoverer of a new celestial object to have the right to suggest a name for it (they still have to approve the name). They're also the group which decided to redefine "planet" to exclude Pluto, for fear that the discovery of more bodies like Eris would result in there eventually being dozens of planets.

Pluto's discovery was purely an accident. Perturbations in the orbits of Uranus and Neptune led astronomers to speculate on the existence of a 9th planet. Based on those perturbations, the approximate location of the 9th planet was calculated. Tombaugh was tasked with looking for a planet around that location when he discovered Pluto. But its mass was insufficient to be causing the perturbations.

Modern measurements of the mass of Uranus and Neptune have shown the orbits were correct; the assumptions about their masses were wrong. So there were no perturbations, and Pluto was discovered because it just happened to be in a location specified by a miscalculation.


RE: Pluto
By JKflipflop98 on 5/13/2012 11:15:46 AM , Rating: 3
Lots of discoveries were "just an accident". That doesn't make them any less of a discovery.


RE: Pluto
By Belard on 5/14/2012 6:10:03 PM , Rating: 2
Who accidentally discovered Mars?

I wonder who discovered the moon first?


What?
By WeaselITB on 5/11/2012 5:16:45 PM , Rating: 1
quote:
... the solar system's nine planets (or 10, if you count Pluto) devoured all but a handful of these smaller bodies.

Ah, yes. The so-called "Planet X" apparently strikes again ... http://en.wikipedia.org/wiki/Planets_beyond_Neptun...

quote:
That phase of the expedition is to head towards Ceres, the solar system's only dwarf planet.

Err, what? There are 5 IAU officially recognized dwarf planets -- Ceres, Eris, Haumea, Makemake, and Pluto, and once we've fully explored the Kuiper belt, we'll probably be in the hundreds. There are at least another dozen or two that just haven't been fully documented and accurately categorized yet.




RE: What?
By Solandri on 5/12/2012 3:55:44 PM , Rating: 2
He probably meant Ceres is the only dwarf planet within the inner solar system (isn't a trans-Neptunian object). It orbits between Jupiter and Mars, as Vesta does.


RE: What?
By Visual on 5/14/2012 9:10:14 AM , Rating: 2
He probably did, but still he wrote it incorrectly and the comment above is valid.

Also, I am very curious what is the definition of a southern bottom. And then also southern top and northern bottom.


So?
By DennisB on 5/14/2012 1:18:01 PM , Rating: 2
quote:
NASA's first ion probe studies planetoid;

After 14 years of Deep Space One...

The new planet definition disregards the possibility of more than one planet in a near same orbit. Who knows, maybe Pluto becomes a planet again once the orbit-clearing rule becomes outdated.




RE: So?
By DennisB on 5/14/2012 1:28:34 PM , Rating: 2
Who cares?
By GmTrix on 5/14/2012 9:55:40 AM , Rating: 2
Can anyone explain to me why everyone gets all worked up about whether or not pluto is a planet? Does it change how it orbits the sun or what its made of if we call it one thing or another? No. Who cares, it's just a name...




good and cheap
By Ashley001 on 5/15/2012 4:01:37 AM , Rating: 2
w w w . b u l l j o r d a n . c o m

I tide fashion

wander on the beach with fashion

Good-looking, not expensive

F r e e t r a n s p o r t




asdfasdkljfaldskjflksd
By Ashley001 on 5/15/2012 4:04:15 AM , Rating: 2
w w w . b u l l j o r d a n . c o m

I tide fashion

wander on the beach with fashion

Good-looking, not expensive

F r e e t r a n s p o r t




Planets
By sonofhistory on 5/11/12, Rating: -1
RE: Planets
By TSS on 5/11/12, Rating: -1
RE: Planets
By Jeremy87 on 5/11/2012 7:56:24 PM , Rating: 2
Mercury is bigger than Pluto, so the size argument doesn't have to mean anything.

But it's not just about the size. It's about what Pluto is made of, and its orbit's size and shape.
And it's just one of many similar objects out there. You can draw the line before Pluto, but not after it without including hundreds of others.


RE: Planets
By e36Jeff on 5/11/2012 11:00:57 PM , Rating: 2
Mercury has a radius of better than double Pluto's and its volume and mass are both an order of magnitude larger. Beyond that Mercury has cleared its orbit of debris, which Pluto has not done. The fact that Pluto has not cleared the debris from its orbit factors much larger into its downgrade than its size.


RE: Planets
By TSS on 5/12/12, Rating: -1
RE: Planets
By deathwombat on 5/12/2012 12:04:55 PM , Rating: 3
quote:
the volume and mass are still not larger then the largest moons. I don't see why a mercury that formed near jupiter and a mercury that formed near the sun should be considered different.


One orbits the Sun, the other orbits Jupiter. Planets orbit stars, moons orbit planets. Size isn't a consideration in that definition; the object is classified based on the object whose gravity has captured it.

quote:
So what are those then? Solar moons?


They're planets, unless they've sparked nuclear fusion, in which case they're stars.


RE: Planets
By Solandri on 5/12/2012 4:00:17 PM , Rating: 2
quote:
That and i think it's largely the sun responsible for taking out debris in unstable orbits around mercury

Two-body orbits (e.g. sun + Mercury, or sun + debris) are stable. The sun cannot clear debris from Mercury's orbit.

You need three bodies interacting in an orbit for there to be any instability and thus any debris clearing. Which is Mercury has done.


RE: Planets
By Belard on 5/14/2012 6:53:18 PM , Rating: 2
quote:
i think it's largely the sun responsible for taking out debris in unstable orbits around mercury, either through gravity or just plain heat.


That is WHY you are not in charge of these things. That and that you don't understand the difference between a planet and moon.

quote:
How about we set the discussion in stone when we have a larger sample base on what

For what reason? We already know what defines a planet.


RE: Planets
By deathwombat on 5/11/2012 11:22:31 PM , Rating: 3
Mercury is a planet because it captured all of the matter in its orbit. Pluto is only a dwarf planet because it didn't capture all of the material in its orbit, which is full of icy objects, just as Ceres and Vesta's orbit is full of asteroids. The definition of a planet is an object is "an object that orbits the Sun that is large enough to have become round under the force of its own gravity (hydrostatic equilibrium) and cleared its orbital path". That's why Mercury is a planet and Pluto isn't. Science is fun!


RE: Planets
By Reclaimer77 on 5/12/12, Rating: 0
RE: Planets
By deathwombat on 5/12/2012 12:00:52 PM , Rating: 2
It is absolutely reasonable to expect a planet to dominate the local gravity within its orbit sufficiently to swallow or capture all of the material in its orbit. (This allows the planet to have moons and have stuff stuck in its Lagrange points). Earth did it. Mercury did it. Ceres didn't and Pluto didn't. They aren't big enough.

Charon is indeed a large moon. Hydra, Nix, and the unnamed newbie aren't nearly large enough to have achieved hydrostatic equilibrium, so don't tell me that Pluto has four "full moons".


RE: Planets
By Reclaimer77 on 5/12/2012 12:52:56 PM , Rating: 1
quote:
It is absolutely reasonable to expect a planet to dominate the local gravity within its orbit sufficiently to swallow or capture all of the material in its orbit.


And it's just as reasonable to dismiss this as being an important factor. We simply do not have enough understanding of the Universe, or the ability to observe enough planets and other Solar Systems, to assume we have a large enough sampling group to make this determination.

Pluto has moons, it has an atmosphere, it has hydrostatic equilibrium. It's a planet.


RE: Planets
By Solandri on 5/12/2012 4:15:56 PM , Rating: 3
Mathematically, it's actually a very good definition for a planet. Aside from the Lagrange points, a large-enough body in an orbit will clear the rest of the orbit of debris. It's a very static definition, one that's unlikely to change over time short of some catastrophic interstellar event. We don't need to observer other stellar systems to know this - it can be mathematically derived.
http://en.wikipedia.org/wiki/Lagrangian_point

The other definitions you give don't work nearly as well:

- If having a moon makes you a planet, Mercury and Venus have no moons and thus aren't planets. It's also arguable whether Mars' moons are really moons, rather than just captured rocks.
- If having an atmosphere makes you planet, Mercury has no atmosphere and thus isn't a planet. Titan and Triton (moons around Saturn and Neptune) have atmospheres, and thus are planets.
- If having hydrostatic equilibrium makes you a planet, then most of the moons in our solar system are planets. Comets are planets.


RE: Planets
By Reclaimer77 on 5/12/2012 7:52:15 PM , Rating: 2
It's a very ambiguous definition. Not even Earth has cleared it's orbit of all the "near Earth object" comets and asteroids. Why the double standard?

quote:
The other definitions you give don't work nearly as well:


I never said those were "definitions". Merely a supporting argument. Pluto has enough mass to gather several round moons of various sizes in stable orbits. Surely this counts for something? It's round. It has an atmosphere. It's clearly not a moon of Neptune. It has moons of stable orbits. You know what? That works for me.

This is still an active debate in the astrological community. I realize that it seems I often take a controversial stance to promote discussions, but I feel perfectly comfortable in this case supporting Pluto as a planet.

quote:
http://kencroswell.com/HD45364.html


Around the orange dwarf star named HD 45364 where two gas giants cross orbits? Are each of those gas giants now to be considered dwarf planets?

What too about the possibility of the double planets – and one’s that end up on collision courses through orbital chaos like Earth and the Mars-sized world that struck our Earth leading to the formation of the Moon? Do such worlds lose planetary status when they're on collision course but have it before that?

The IAU definition leads to absurd consequences that make no sense. And causes far more problems and uncertainty with each new potential discovery. We do indeed need a better definition than the IAU one which restores Pluto’s planethood.


RE: Planets
By Solandri on 5/13/2012 3:19:23 PM , Rating: 2
quote:
Around the orange dwarf star named HD 45364 where two gas giants cross orbits? Are each of those gas giants now to be considered dwarf planets?

The IAU definition requires a planet to have cleared its own orbit of other debris (i.e. also in its orbit, the lagrange points I posted excepted). The two gas giants you mention do not share the same orbit - they cross orbits. So they do not run afoul of the IAU definition. As I said, it's a very good definition. Arbitrary, yes, but after a lot of thought it's a lot less arbitrary than anything else I could think of or what you've suggested.

quote:
This is still an active debate in the astrological community. I realize that it seems I often take a controversial stance to promote discussions, but I feel perfectly comfortable in this case supporting Pluto as a planet.

I really don't see what the problem is. All they've done is refined the definition to make two classes of planetoids - planets and dwarf planets. I think it was a sensible reaction to the discovery that there's a helluva lot of other stuff like Pluto orbiting our sun way out there. And it also neatly takes care of Ceres and Vesta, which are so large I was always uncomfortable calling them asteroids.

They're not saying Pluto isn't a planet. They're saying the old definition of planet covered too large a range of stuff, so they're addition more sub-definitions.

quote:
What too about the possibility of the double planets

Double planets (2 planets sharing the same orbit) are impossible unless the much smaller one is in the larger's lagrange point, or (if they're similar massed) they're in each others' lagrange points. Outside of the lagrange points, the orbits are not stable, and eventually the two collide. This is the "clearing its orbit of debris" process. In practicality, gravity from other planets makes even the lagrange points relatively unstable over millions of years. It sounds like you think the definition is arbitrary because you don't understand the orbital mechanics behind it.

quote:
and one’s that end up on collision courses through orbital chaos like Earth and the Mars-sized world that struck our Earth leading to the formation of the Moon? Do such worlds lose planetary status when they're on collision course but have it before that?

If a huge asteroid on a hyperbolic orbit flew in and smashed Mars into little bits which then failed to coalesce, then yes Mars would no longer be a planet. It would effectively have been destroyed.

After the Earth was struck to form the moon, it re-coalesced and its gravity re-captured all the debris. So Earth is still a planet. If you want to be pedantic, I suppose you could call the current Earth Earth2, and the previous Earth-moon body Earth1.


RE: Planets
By SPOOFE on 5/12/2012 5:02:01 PM , Rating: 1
quote:
And it's just as reasonable to dismiss this as being an important factor.

No, that's no reasonable at all. The reason we have words is for descriptive communicative processes. If we went with your proposals, our words would be less descriptive, and thus less useful.

All this protesting and whining on your part just because you can't adjust the part of your brain that thinks "Pluto Equals Planet". Sad.


RE: Planets
By Reclaimer77 on 5/12/2012 7:57:51 PM , Rating: 2
quote:
All this protesting and whining on your part just because you can't adjust the part of your brain that thinks "Pluto Equals Planet". Sad.


And your brain is apparently thinking "appeal to authorities, go back to Jersey Shore. Me likey Snookie".

I think my brain is doing just fine. You know, thinking? Questioning things? Learning? Forming thoughts of my own.

But yes, a discussion about Pluto is REALLY the appropriate place to make it personal and attack someone over it. Bravo Spoofe.


RE: Planets
By FaaR on 5/12/2012 3:09:26 PM , Rating: 2
Reclaimer, I suggest you work on repealing the law of gravity next.

FIGHT AUTHORITY!!!


RE: Planets
By 91TTZ on 5/14/2012 11:58:41 AM , Rating: 1
Why does everyone keep rating Reclaimer down? It's not like he's spouting ridiculous nonsense, he's merely stating facts which muddy the waters. The problem with that is that depending on when you grew up, what is considered "clear and logical" one year can be completely repealed some time later.

It really does come down to politics within whatever organization makes the rules. They make a rule and then want you to internally rationalize the rule. Questioning the rule is discouraged. Some time later management changes and a new rule takes effect. They discard the old rule, claiming it to be invalid, and then enact a new rule. Once again they want you to internally rationalize it and accept it as indisputable fact.

This has gone on for ages. In the 1920's if you had a beer with your friends you were just having a good time. Everyone knows you should eat, drink, and be merry. In the 1930's during Prohibition alcohol was banned, as it should be. After all alcohol is a dangerous and immoral substance and cannot be enjoyed responsibly in any amount. Some people drank but they were troublemakers, the kind of people that create crime and the kind of people I don't want to be around. Then Prohibition was lifted and we could enjoy a beer again, as we should be able to. Everyone knows that you can drink responsibly so it makes sense.

When I was in school everyone knew that Pluto was a planet. Sure, it was small, in a weird orbit, and very far away but that didn't change the fact that it was a planet. If you claimed that those things made it not a planet you were an idiot, since we all knew it's a planet. Then some time passed and the statement was made that those things DID make it not a planet. There was some arguing but that all passed. Now the "common knowledge" is that Pluto is not a planet, and you'd be an idiot if you claimed otherwise.

Basically if you hang around long enough you'll see that many determinations are completely arbitrary and there's no use trying to justify them.


RE: Planets
By Reclaimer77 on 5/11/12, Rating: 0
RE: Planets
By BillyBatson on 5/12/2012 1:39:29 AM , Rating: 1
I don't understand your argument? It's man who is classifying objects in space therefor it's presumptuous? Do you know of some sort of 10 commandments of space that God sent down we don't know about? Man classifies everything and none of it starts off as right or wrong they are just labels we use but as long as it continues to follow a formula and set guidelines then they aren't just words.
I'm not going to say people don't like change but I will say people like familiar things and we all grew up with Pluto being called a planet and sayin otherwise takes away that familiarity... But the new generation won't know Pluto as a planet and that will be the norm. No matter what you thi I of it though Pluto is still out there hasn't changed and doing what it's been doing for eons.


RE: Planets
By Reclaimer77 on 5/12/2012 2:02:25 AM , Rating: 1
quote:
Man classifies everything and none of it starts off as right or wrong they are just labels we use but as long as it continues to follow a formula and set guidelines then they aren't just words.


Well since I am a man, I choose to label Pluto a planet :)

And by the way, let's not pretend that this "dwarf-planet" classification isn't HIGHLY controversial in the scientific community. I've studied both arguments and I find merits in each one. But don't kid yourself into thinking everyone is on board with this castration of Pluto's status.

I simply don't see any compelling reasoning in the requirement that a planet "must clear it's own orbit" besides the fact that this was a convenient criteria in light of newer discoveries that 12+ objects in our Solar System could be called a "planet".

http://www.thespacereview.com/article/1504/1


RE: Planets
By bebimbap on 5/12/2012 4:53:32 AM , Rating: 2
Every day is different from the previous. What is hard cold fact one day might become false the next.
If I said today is saturday May 12 2012 today, I would be telling a cold hard fact. If I said the exact same thing tomorrow, I would be either ignorant of the date change, crazy, or lying.
Even Newton's laws were augmented by Einsteins relativity, and even that was augmented with quantum mechanics and "special" relativity.


RE: Planets
By Reclaimer77 on 5/12/2012 10:44:01 AM , Rating: 2
That's a little TOO subjective a viewpoint in a scientific study in my opinion. If I demonstrate today what temperature water boils on my stove, tomorrow that's not going to change. It's going to remain a constant.

Basically we had two factions of astronomers in 2006. One that formed criteria for Pluto being a planet, and one that did the opposite. The anti-Pluto group won in the end, but I don't necessarily see why we should all agree with them. It's hotly contested to this day. There's nothing wrong with still viewing Pluto as a planet. There is no cold hard science behind this, it's all opinion.

As you said, things always change with new evidence. What if we discover a planet five times larger than Earth with ten times the density and five moons, and it hasn't cleared it's own orbit for some unforeseen reason. Do we still call it a "dwarf-planet" and not a real one?


RE: Planets
By Aries1470 on 5/12/2012 3:36:42 PM , Rating: 2
Ok, since I like your debates and logic on the subject, I would like to ask for your opinion, and others ofcourse.

Say, we find a planetoid body, around the size of Pluto, or slightly smaller even, it is "rounded", it has a "rounded" moon or two, it has cleared most of its path, would that classify it as a "planet", but it is located further out than Pluto?

Also, the "its cleared its path", say for arguments sake, there is a large asteroid that is circuling on a silimar orbit, or slightly elliptical that crosses paths with this planet, every so many decades or eon or what have you, just because it has "not cleared" its orbit, it can not be classified as a planet? Just curious, since for all I care to understand then, so many planets should loose their designation, since they can be hit by an asteriod etc, hence, they have "not cleared their path". Neither has Earth in that case... :-)

Just seeking enlightenment.


RE: Planets
By Reclaimer77 on 5/12/2012 7:30:17 PM , Rating: 2
Exactly! You bring up very good points. I do not like the ambiguity of the "cleared it's orbit of objects" criteria. Because as you pointed out, even Earth has a large number of "near Earth objects", comets and asteroids, that routinely cross our orbit and sometimes even hit us.

quote:
Say, we find a planetoid body, around the size of Pluto, or slightly smaller even, it is "rounded", it has a "rounded" moon or two, it has cleared most of its path, would that classify it as a "planet", but it is located further out than Pluto?


Since the IAU didn't specifically designate size and mass requirements for a planet, a misstep perhaps, I would have to say that yes; this theoretical body is a planet.


RE: Planets
By BillyBatson on 5/12/2012 8:17:13 PM , Rating: 2
Just because objects hit us doesn't mean they all came from within our solar system and even when they do doesn't that mean earth is still clearing its orbit or debris? Sort of like sweeping the remaining dust into a dust pan after you've swept in the bulk of the trash? While Pluto doesn't seem to have done much "sweeping" at all and doesn't seem like it's going to start any time soon. You don't see why clearing its orbit should be a prerequisite for being labeled a planet and it doesn't bother me one way or another but it is easy to see why they would introduce this, gravitational force is being factored into what a planet "should be". We can argue that is Pluto is clearing its debris but slowly maybe by our current definition it could become a planet within a few million years (pure guesstimate) but clearing its debris would probably give it more gravitational force due to a new density. By that time though the definition of a planet could be changed.
Maybe we should have different classes of planets like in star trek? M-Class planet = habitable, etc... Pluto probably wouldn't be up high on that classification chart either as far as planets go.

You're a man?.... I'll refrain from cracking a joke lol..... But I did say that follows rules/guidelines. Irony want to make your own classification chart submit it have it voted on by world scientists and it becomes standard then yes I'd follow it, when it comes to labeling they are just words unless the majority of people follow that rule set. If you say the sky is blue but everyone else says its red we'll then what we knew as the color blue before is now called red. Only question would be what spoils you then call the color that used to be known as red? Blue perhaps....


RE: Planets
By SPOOFE on 5/12/12, Rating: -1
RE: Planets
By Camikazi on 5/12/2012 6:23:54 PM , Rating: 2
Pluto was named after the God of the Underworld not after a cartoon dog :P


RE: Planets
By Reclaimer77 on 5/12/2012 7:21:12 PM , Rating: 2
Actually Pluto's feeling are quite sore on this subject. You should be more sensitive! :P

http://www.newscientist.com/blogs/culturelab/2009/...

quote:
As if it's a matter of bias against a ball named after a Disney character


Disney? Whoa bro, trivia FAIL! You lose Jeopardy.


"We shipped it on Saturday. Then on Sunday, we rested." -- Steve Jobs on the iPad launch














botimage
Copyright 2014 DailyTech LLC. - RSS Feed | Advertise | About Us | Ethics | FAQ | Terms, Conditions & Privacy Information | Kristopher Kubicki