Our knowledge of Solar System: Dazzling statistics

[h2ouniverse]

Dazzling statistics on the speed of our progresses in understanding Solar System<br />1/3: Number of bodies<br /><br />Hi all,<br /><br />I had to make the following census recently and would like to share my amazement, and excitation to live this new "golden age" of knowledge.<br /><br />Number of bodies known to mankind in our Solar System:<br /><br />Up to 1600AD: 8<br />Up to 1800AD: 22<br />Up to 1900AD: about 700<br />Up to 1995AD: about 27,000<br />Up to 2000AD: about 62,000<br />By Oct 2007AD: /> 384,000 !!!<br /><br />Of course that is thanks to a new paradigm: CCD.<br /><br />Feel the speed?

 

[yevaud]

Umm, yeah.<br /><br />CCD technology isn't a paradigm. <div class="Discussion_UserSignature"> <p><em>Differential Diagnosis:  </em>"<strong><em>I am both amused and annoyed that you think I should be less stubborn than you are</em></strong>."<br /> </p> </div>

 

[h2ouniverse]

You are right "paradigm" is not appropriate for the CCD technology proper.<br />However the consequence is well a paradigm shift to me: with the subsequent discovery of many objects in Kuiper Belt plus Sedna, this has led to:<br />* re-categorization of planets <br />* increasing perception of the region from Jupiter to Neptune as the "Mid Solar System", no longer as "Outer System", this latter term being more and more used to designate the region beyond Neptune's orbit<br />Regards.

 

[yevaud]

Ok, that's more accurate. The re-thinking is closer to a paradigm. Not a science-wide and entirely new line of thinking, but much closer. <div class="Discussion_UserSignature"> <p><em>Differential Diagnosis:  </em>"<strong><em>I am both amused and annoyed that you think I should be less stubborn than you are</em></strong>."<br /> </p> </div>

 

[h2ouniverse]

I might add as another consequence: the Nice model (large-scale migration of planets)<br />= /> the end of constancy on what ancients regarded as an eternal giant clock, orderly arranged<br />= /> orbits of planets (including Earth) no longer considered stable over long periods<br /><br />Knowing more and more orbital data, even for small bodies, has made the understanding of the system (system in its etymological meaning) progress in a considerable way.

 

[alokmohan]

Can you tell me when we can calculate orbits of NEOs so as to avoid collision?

 

[brellis]

NASA's list of 896 Potentially Hazardous Asteroids <div class="Discussion_UserSignature"> <p><font size="2" color="#ff0000"><em><strong>I'm a recovering optimist - things could be better.</strong></em></font> </p> </div>

 

[alokmohan]

896 dangers hanging around.If astrologers know they will earn lot of money.

 

[h2ouniverse]

Thanks Brellis for this recall,<br /><br />Btw, to illustrate my purpose:<br />Of these 896 objects, most than a half has been discovered since... 2002! = /> in just five years!<br /><br />Regards.

 

[h2ouniverse]

And only 100 before end 1997.<br />This means about 90% of NEO discovered in the last decade.

 

[h2ouniverse]

Dazzling statistics on the speed of our progresses in understanding Solar System <br />2/3: New lands to explore<br /><br />Of course the 40,000 or so new objects discovered every year are small fry for most of them but...<br /><br />Let's consider objects larger than 500km (i.e. than Enceladus, the smallest active body known), known to mankind in the Solar System:<br /><br />1800AD: 21<br />1900AD: 29<br />1990AD: 31<br />2000AD: 35<br />2007AD: 69 !!!<br /><br />As a recall: a 500km+ diameter body means an area to explore, map and anlayze larger than combined areas of the UK and metropolitan France.<br /><br />The rate for discovery of such objects is currently one every three months on average (over the last 7 years).<br /><br />A 1000km+ diameter body means an area to explore, larger than India.<br /><br />The rate for discovery of objects about or larger than 1000km is currently one every year on average over the last 7 years.<br /><br />With such size, many may be differentiated or with some activity. (already suspected for Eris, Quaoar, Orcus, 2003EL61)<br /><br />We need probes!!<br />

 

[3488]

New Horizons 2, 3, 4 & 5 please, but than the discovery of pink flying elephants will probably<br />be more likely <img src="/images/icons/tongue.gif" /> .<br /><br />In all seriousness the KBOs you mentioned are thought to be differentiated & / or have been active.<br /><br />However we will at least get a decent look at the Pluto Charon pair though.<br /><br />Andrew Brown. <div class="Discussion_UserSignature"> <p><font color="#000080">"I suddenly noticed an anomaly to the left of Io, just off the rim of that world. It was extremely large with respect to the overall size of Io and crescent shaped. It seemed unbelievable that something that big had not been visible before".</font> <em><strong><font color="#000000">Linda Morabito </font></strong><font color="#800000">on discovering that the Jupiter moon Io was volcanically active. Friday 9th March 1979.</font></em></p><p><font size="1" color="#000080">http://www.launchphotography.com/</font><br /><br /><font size="1" color="#000080">http://anthmartian.googlepages.com/thisislandearth</font></p><p><font size="1" color="#000080">http://web.me.com/meridianijournal</font></p> </div>

 

[MeteorWayne]

That 22 in 1800 seems high to me, but I'll have to ponder it a bit and<br />"Make a list and check it twice <img src="/images/icons/smile.gif" /> " <div class="Discussion_UserSignature"> <p><font color="#000080"><em><font color="#000000">But the Krell forgot one thing John. Monsters. Monsters from the Id.</font></em> </font></p><p><font color="#000080">I really, really, really, really miss the "first unread post" function</font><font color="#000080"> </font></p> </div>

 

[halcyondays]

I reckon there were 21 objects of 500 kilometres or greater in the solar system known in 1800 : Sun, Mercury, Venus, Earth, Moon, Mars, Jupiter, Callisto, Io, Europa, Ganymede, Saturn, Titan, Enceladus, Tethys, Dione, Rhea, Iapetus, Uranus, Titania, Oberon.<br /><br />Did I miss one ? I assume no asteroids, the first of which was discovered on 1/1/1801.

 

[3488]

Neptune & Triton were not known until 1846.<br /><br />Andrew Brown. <div class="Discussion_UserSignature"> <p><font color="#000080">"I suddenly noticed an anomaly to the left of Io, just off the rim of that world. It was extremely large with respect to the overall size of Io and crescent shaped. It seemed unbelievable that something that big had not been visible before".</font> <em><strong><font color="#000000">Linda Morabito </font></strong><font color="#800000">on discovering that the Jupiter moon Io was volcanically active. Friday 9th March 1979.</font></em></p><p><font size="1" color="#000080">http://www.launchphotography.com/</font><br /><br /><font size="1" color="#000080">http://anthmartian.googlepages.com/thisislandearth</font></p><p><font size="1" color="#000080">http://web.me.com/meridianijournal</font></p> </div>

 

[h2ouniverse]

For MeteorWayne:<br /><br />The 22 are the 21 quoted by Halcyondays + Mimas, discovered by Herschel in 1789.<br /><br />But that is true Halcyondays, I forgot to remove Mimas from the pre-1800 list for bodies <500km+.<br />I edit my post accordingly.<br /><br />Best regards.

 

[3488]

Mimas is only 392 KM across. So I'm afraid not.<br /><br />Andrew Brown. <div class="Discussion_UserSignature"> <p><font color="#000080">"I suddenly noticed an anomaly to the left of Io, just off the rim of that world. It was extremely large with respect to the overall size of Io and crescent shaped. It seemed unbelievable that something that big had not been visible before".</font> <em><strong><font color="#000000">Linda Morabito </font></strong><font color="#800000">on discovering that the Jupiter moon Io was volcanically active. Friday 9th March 1979.</font></em></p><p><font size="1" color="#000080">http://www.launchphotography.com/</font><br /><br /><font size="1" color="#000080">http://anthmartian.googlepages.com/thisislandearth</font></p><p><font size="1" color="#000080">http://web.me.com/meridianijournal</font></p> </div>

 

[h2ouniverse]

you're so fast Andrew, you succeeded in posting at 2:18 just as I was editing my post at 2:17!

 

[vandivx]

"Of course that is thanks to a new paradigm: CCD."<br />--<br /><br />I'd take it standing as you put it, good evaluation IMO<br /><br />but pitty you talk only about solar system, CCDs came into their own when it comes to deep space exploration like measuring redshifts by (semi)automatized techniques which in conjunction with computers made veritable revolution in astronomy<br /><br />vanDivX <div class="Discussion_UserSignature"> </div>

 

[MeteorWayne]

Well, the solar system is the subject of this thread..... <div class="Discussion_UserSignature"> <p><font color="#000080"><em><font color="#000000">But the Krell forgot one thing John. Monsters. Monsters from the Id.</font></em> </font></p><p><font color="#000080">I really, really, really, really miss the "first unread post" function</font><font color="#000080"> </font></p> </div>

 

[h2ouniverse]

Well, one has to select a perimeter when dealing with numbers.<br />The exoplanets would deserve such a statistic as well (although I get the impression that the exoplanets discovery rate is currently more or less constant, not exponential as for Solar System). <br />For deep sky astronomy, I would rather place space telescope and adaptative optics as the enabling disruptive technologies.

 

[vandivx]

"For deep sky astronomy, I would rather place space telescope and adaptative optics as the enabling disruptive technologies."<br /><br />I suppose if you take the view of 'number of bodies discovered' but even then<br /><br />not being expert so I won't argue but I'd still think invention of CCDs takes the medal because of the 'mechanization' of observation it made possible, those you talk are about improved precission and clarity etc but can't beat the import of CCDs for astronomy although they are about different aspect of it than those you mention<br /><br />vanDivX <div class="Discussion_UserSignature"> </div>

 

[h2ouniverse]

a point for you. But is mechanization a factor for extrasolar targets? (for professionals)<br /><br />Of course for amateur astronomers, CCD is a revolution for deep sky observation.

 

[brellis]

<font color="yellow">Up to 1600AD: 8<br />Up to 1800AD: 22<br />Up to 1900AD: about 700<br />Up to 1995AD: about 27,000<br />Up to 2000AD: about 62,000<br />By Oct 2007AD: /> 384,000 !!! </font><br /><br />As we get more precise estimates of mass and constitution of the rings of the outer planets, and subsequently more accurate measurements of Kuiper and Oort regions, we'll soon be able to estimate pretty accurately how many little pebbles and then even grain-sized objects are in our solar system - how many billions and trillions will that be? <img src="/images/icons/cool.gif" /> <div class="Discussion_UserSignature"> <p><font size="2" color="#ff0000"><em><strong>I'm a recovering optimist - things could be better.</strong></em></font> </p> </div>

 

[h2ouniverse]

Dazzling statistics on the speed of our progresses in understanding Solar System <br />3/3: Number of active bodies <br /><br />Hi all, <br />Numerous new bodies are fine but if they are dead balls, they are of limited interest.<br />So, let's look now at the bodies known to have "activity" (as opposed to geological death): Volcanism, Cryovolcanism, Ice convection or liquid water layers, Liquid core, Current resurfacing processes, Evaporation/condensation cycles<br /><br />RECENT DISCOVERIES OF ACTIVITY ON SOLAR SYSTEM BODIES IN THE TWO PREVIOUS DECADES<br />Venus, Mars, Io and the four giants were already evidenced as “active†before 1987<br />Since then, I come to 11(*) [15?] additional bodies with indication of activity, starting from Triton’s fly-by by Voyager:<br /><br />Triton (1989) (cryovolcanism)<br />Europa (1997) (water or slush layers)<br />Ganymede (2000) (water or slush layers)<br />Callisto (2001) (water or slush layer)<br />Pluto (2002) (atmospheric cycle)<br />Ceres (TBC) (2003) (differentiation evidenced) (frost cycle?)<br />Titan (2005) (atmospheric cycles, rains, lakes, cryovolcano)<br />Eris (TBC) (2005) (methane cycle)<br />Enceladus (2006) (resurfacing, vents)<br />Dione (TBC) (2007) (vents ?)<br />Mercury (2007) (molten core)<br />Quaoar (2007) (cristalline ice)<br />2003EL61 (2007) (cristalline ice)<br />Charon (2007) (cristalline ice)<br />Iapetus (2007) (surface substance transfers by thermal segregation)(currently? TBC)<br /> <br />I am aware this list is subjective. Any comment or correction? <br /><br />(*) the 15-11=4 ones with reservation: Ceres, Eris, Dione, Iapetus, for which afaik there is not yet ascertained evidence of on going activity<br />(**) I have not included the Moon, with the 2006 discoveries pointing to potential recent outgassing <br />(***) I guess Andrew will protest about the TBC on Dione