the tenth planet

[mamakos]

Does anyone have knowledge or information on these new 'planets' which are apparently being found in the outer reaches of our solar system?<br />If you do, then please enlighten me as to the current situation.

 

[qso1]

Here are links to at least three planets discovered since Pluto that I can think of off the top of my head, lots of data by the way.<br /><br />http://en.wikipedia.org/wiki/90377_Sedna<br /><br />http://en.wikipedia.org/wiki/50000_Quaoar<br /><br />http://en.wikipedia.org/wiki/2003_UB313 <div class="Discussion_UserSignature"> <p><strong>My borrowed quote for the time being:</strong></p><p><em>There are three kinds of people in life. Those who make it happen, those who watch it happen...and those who do not know what happened.</em></p> </div>

 

[mamakos]

Thanks for that.<br /><br />Also, could someone tell me what the current definition of a 'planet' is now. Aparently it is changing due to all the new orbital bodies being found, which currently fit into the specifications, but do not seem to fit logically.

 

[qso1]

Thats kind of in a state of turmoil at this point. I suspect they will redefine planet within the next few years. One reason, some say Pluto does not qualify as a planet while others say it is. Now that we have these new planets which are close in size to Pluto, but are not unlike KBOs, the debate continues. <div class="Discussion_UserSignature"> <p><strong>My borrowed quote for the time being:</strong></p><p><em>There are three kinds of people in life. Those who make it happen, those who watch it happen...and those who do not know what happened.</em></p> </div>

 

[mamakos]

Some objects defined as Kuiper Belt Objects are bigger than Mars, yet have not been given planital status. If anything does sort itself out in this matter, please inform me.<br /><br />Sometime in the past couple of months, i heard about Pluto having a second moon. What is the staus of this?

 

[fingle]

<blockquote><font class="small">In reply to:</font><hr /><p>Some objects defined as Kuiper Belt Objects are bigger than Mars, yet have not been given planital status. If anything does sort itself out in this matter, please inform me. <p><hr /></p></p></blockquote><br /><br />I must be losing touch, when did this happen ? Do you have a link i can goto and read about those objects ?<br /><br /><blockquote><font class="small">In reply to:</font><hr /><p>i heard about Pluto having a second moon. What is the staus of this?<p><hr /></p></p></blockquote><br /><br />Two more moons, read about it here Space.com Two More Moons discovered orbiting Pluto<br /><br /><img src="/images/icons/smile.gif" /><br /> <div class="Discussion_UserSignature"> </div>

 

[rfoshaug]

They haven't discovered Kuiper Belt Objects bigger than Mars as far as I know. But they have discovered one (UB313?) that is bigger than Pluto.<br /><br />The International Astronomical Union is, as far as I know, hard at work deciding how to find a way of determining how they should go about to find out how they will decide who to invite to a discussion about how they should try to find a definition of the word "planet". It will take time. For now the 9 "classic" planets are officially planets, and the other objects are not classified as planets yet.<br /><br /><br />The problem is to decide where to draw the line between planets and other objects.<br /><br />Some people say we have 8 planets and that Pluto is not a planet, because it clearly has been formed in a different way to the other planets (gas giants) out there. Although if objects as diverse as Mercury and Jupiter both are planets, then Pluto and Sedna and the other large Kuiper Objects could very well be called planets as well.<br /><br />Other say we have 9 planets because a planet is a cultural and historical term, not a scientific one, while others (myself included) say that Pluto and any other large object out there should be classified as planets - which of course leads to the question of what a "large" object is.<br /><br /><br />There are objects ranging in size from dust grains to pebbles, rocks, boulders, mountains and so on all the way up to the planets we know in our solar system. The line has to be drawn somewhere. Every dust grain is not a planet.<br /><br /><br />It has been speculated that the International Astronomical Union will stop using the word "planet" and instead divide them into categories, like "Terrestrial planets", "Gas giant planets", "Minor planets" and that Kuiper Objects (including Pluto) will be in a separate category of planet.<br /><br /><br />Pluto, as mentioned in a previous post, has been confirmed to have 3 moons. Strangely enough, as ever smaller objects are found orbiting Jupiter an <div class="Discussion_UserSignature"> <p><font color="#ff9900">----------------------------------</font></p><p><font color="#ff9900">My minds have many opinions</font></p> </div>

 

[alokmohan]

The International astronomical union is to meet soon.Until then keep calling pluto a planet.It is by convention we call it planet.When Tombough discovered it in 1930,he thogh it waqs Lowells tenth planet.

 

[mamakos]

Continuing on this line as 'planets' as the topic, does anyone know aproximately how manyy exoplanets have been found? I think that they are well into the hundreds by now.

 

[harmonicaman]

Check out this site for the latest on Extrasolar planets; latest total, 192!<br /><br />The Extrasolar Planets Encyclopaedia<br /><br />Jean Schnieder has been hard at work keeping the list up-to-date for 11 years!<br />

 

[rfoshaug]

So far about 130 exoplanets have been discovered.<br /><br />http://www.space.com/scienceastronomy/050509_exoplanet_review.html<br /><br />These are exiting times! <img src="/images/icons/laugh.gif" /> <br /><br /><br />Edit: Sorry, it seems that there are more of these planets out there than this article says. I now see that it is about a year old. <div class="Discussion_UserSignature"> <p><font color="#ff9900">----------------------------------</font></p><p><font color="#ff9900">My minds have many opinions</font></p> </div>

 

[mamakos]

Thanks everyone.<br /><br />Btw, does anyone happen to know when this massive storm on Saturn is meant to be dying out? It seems to have been on it's 'last legs' for ages.

 

[qso1]

Thats true, and like government, science can be slow when it comes to something somewhat political such as deciding how astronomical bodies are classified. If I hear anything, I'll post it. <div class="Discussion_UserSignature"> <p><strong>My borrowed quote for the time being:</strong></p><p><em>There are three kinds of people in life. Those who make it happen, those who watch it happen...and those who do not know what happened.</em></p> </div>

 

[qso1]

rfoshaug:<br />Pluto, as mentioned in a previous post, has been confirmed to have 3 moons. Strangely enough, as ever smaller objects are found orbiting Jupiter and Saturn, nobody seems to discuss what the size limits for a moon is. If there is no limit, Saturn has billions of moons that form its rings.<br /><br />Me:<br />Thats for sure, in fact, one of the asteroids that Galileo flew by, Ida if I'm recalling right...has a tiny little moon called Dactyl. <div class="Discussion_UserSignature"> <p><strong>My borrowed quote for the time being:</strong></p><p><em>There are three kinds of people in life. Those who make it happen, those who watch it happen...and those who do not know what happened.</em></p> </div>

 

[vogon13]

I'm having a tough go proving it, but I feel a few existing moons in our solar system in the distant past, had moons of their own.<br /><br />Neat if true.<br /><br /><br /> <div class="Discussion_UserSignature"> <p><font color="#ff0000"><strong>TPTB went to Dallas and all I got was Plucked !!</strong></font></p><p><font color="#339966"><strong>So many people, so few recipes !!</strong></font></p><p><font color="#0000ff"><strong>Let's clean up this stinkhole !!</strong></font> </p> </div>

 

[qso1]

Could well be a possibility. <div class="Discussion_UserSignature"> <p><strong>My borrowed quote for the time being:</strong></p><p><em>There are three kinds of people in life. Those who make it happen, those who watch it happen...and those who do not know what happened.</em></p> </div>

 

[mamakos]

Are you trying to say that in the far and distant past, some of our larger solarsystem moons had small moons of their own? That would be interesting if any were found today.

 

[nexium]

Likely many moons have millimeter size and smaller moons. Neil

 

[rfoshaug]

<blockquote><font class="small">In reply to:</font><hr /><p>Btw, does anyone happen to know when this massive storm on Saturn is meant to be dying out? It seems to have been on it's 'last legs' for ages.<p><hr /></p></p></blockquote><br /><br />Saturn is quite a stormy planet with fast winds (although I think Neptune has the fastest winds recorded in our solar system). It has some large oval storms racing around in its upper cloud layers, quite similar to the "Great Red Spot" on Jupiter, which I think may be the one you're thinking of.<br /><br />This huge storm, considerably larger than Earth, has been observed since the invention of the telescope in the 1600's so nobody knows how old it really is. All we know is that it has been around for centuries.<br /><br />It is visible through telescopes as a red (or at least reddish) oval spot on Jupiter. In recent years it has become weaker and more "salmon colored" and it is suspected that it is about to die out. This may of course take several decades. The storm might also grow stronger again and not die out at all.<br /><br />In addition to the great red spot, Jupiter has a very dynamic atmosphere with lots of storms appearing and disappearing as the clouds in different bands around the planet move at different speeds. Actually, a new, smaller red spot has been discovered on Jupiter recently. This is a new storm that seems to be growing and may be another large storm that might last for centuries. It might also merge with the large spot to form an even greater storm.<br /><br />More info here:<br /><br />http://www.space.com/scienceastronomy/060303_jupiter_spot.html<br /><br /><img src="/images/icons/smile.gif" /> <div class="Discussion_UserSignature"> <p><font color="#ff9900">----------------------------------</font></p><p><font color="#ff9900">My minds have many opinions</font></p> </div>

 

[mamakos]

What are the current methods for discovering exoplanets? ...and how do they work?

 

[harmonicaman]

<b>Mamakos -</b><br /><br />Here's a clever chart which shows the various methods used to detect Extrasolar Planets (it's a pdf. file). This chart and much more information can be found here.

 

[mamakos]

Great... thanks a lot.

 

[doubletruncation]

<blockquote><font class="small">In reply to:</font><hr /><p>What are the current methods for discovering exoplanets? ...and how do they work?<p><hr /></p></p></blockquote><br /><br />There are a whole bunch of methods. So far the method that has been by far the most successful in terms of the number of planets that have been found is to look for doppler shifts in a star's spectrum caused by the planet pulling slightly on the star as it orbits it - this method gives you a lower limit on the mass of the pulling object. The second most successful method has been to search for planets that pass in front of (said "transit") their star from our perspective. In that case people monitor the brightnesses of tens of thousands of stars and look for the 1 or 2 that show a slight, repetitive, flat-bottom dip in the brightness over time. There are a lot of things that can mimic that signal, so when you find one you have to look for the doppler shifts in the spectrum to confirm that it is a planet. Planets found this way can give you a lot more information, for one thing you can measure the radius of the planet and also get the actual mass (not just a lower bound), which tells you the density, and hence something about its physical makeup. People have been able to measure the amount light reflected by the planet in a few cases (by looking for a dip in brightness when the planet passes behind the star), and have also been able to learn about the atmospheres of planets by effectively measuring the radius of the planet at different wavelengths of light. Another method that has been successful used to find a few planets is gravitational microlensing. Basically, if something passes right in front of a light source, its gravity can act like a lens to bend the light and cause the background light source to look brighter. In practice people look at very dense starfields (like the galactic bulge) and look for stars that become suddenly brighter in a characterstic way. You can infer that a fainter <div class="Discussion_UserSignature"> </div>

 

[agnau]

I posted my personal preference for deliniating cosmic mass on my blog see the post http://star-colony.blogspot.com/2006/04/nomenclature.html<br />Of course, not every one will agree with my deliniations, but it makes very clear what would and would not be a planet as part of the definitions I used.

 

[doubletruncation]

<blockquote><font class="small">In reply to:</font><hr /><p>I posted my personal preference for deliniating cosmic mass on my blog<p><hr /></p></p></blockquote><br /><br />Interesting. Just a comment is that Uranus and Neptune may not fall under any of these catagories. Uranus, for example, may have a rocky core that's quite a bit more than 2% the mass of the planet, but I don't think you would call Uranus a rocky planet. Also note that planets bigger than Earth but smaller than the ice giants (Neptune and Uranus) may have substantial cores/mantles but may also have no rocky surface (instead a giant water ocean that may change eventually into the mantle). Also, for the stars definition, I don't think the Sun for example actually has the majority of its mass presently participating in fusion. The definition people currently use for this is that it's a star if it can support fusion of ordinary hydrogen into helium in its core, it's a brown dwarf it it can't quite manage ordinary hydrogen fusion but can manage deuterium fusion, and if it can't even manage that it's a planet or something else. But these distinctions may not be the most relevant ones. <div class="Discussion_UserSignature"> </div>