Dear Max: I got out the October Discover and looked at the article again. A few astronomers interested in comet orbits think a group of them may have been caused to head for us by an object in the Oort cloud five times the size of Jupiter 2 trillion miles away that orbits Sun once in five million years. Another NASA telescope to be launched next July may find it.
"Gee, just like the sun!" This object, though huge is not hot enough to emit any light, and is so far away from any source of light that it is exceedingly dim. And it is moving so very slowly that photographs at six month intervals to use parallax to pick it out by its shift in position so far have not found it.
Thanks Max! Although I recognize that many of us are not disposed to being noun-verbers (nouns-verber?), I do like the result of verbificating "gist". I also admire the candor of the architectifiers of the software you describe.
Is there another word out there that would serve in the place of the verbed "gist"?
p.s. - in writing this post, my fingers insisted on typying "noun-berber" twice - which brought to mind images of the pack of us, mounted on our dromedaries, lugging our nouns 'cross the desert wastes, off to trade with the verb-Tuaregs at Conjunction Junction
Max, I wasn't particularly impressed with the article. There really nothing new there. The essay at http://geobeck.tripod.com/frontier/planet.htm gives a much more thorough and much more amusing account of the science involved, plus other interesting matters.
Dear Keiva: Whatever your objections to the Discover story, the URL you gave is to an article by Isaac Azimov which makes no mention of the Oort cloud.
Incomplete. Knowledge from other Asimov: A further planet was hypothesized as an explanation for the irregularity in Uranus's orbit. Searching for that planet, Neptune was discovered.
A further planet was hypothesized as an explanation for the irregularity in Neptune's orbit. Searching for that planet, Pluto was discovered in the 1930's.
However, satellite probes (in the 1970's, I think) revealed that Pluto is quite small -- too small to account for the Neptune irregularities. Ever since then, it's been hypothesized that there's something else, further out. The astronomer featured in Dicover is not, in this, working on anything new and novel. Nor is he, by his own admission, anywhere near a breakthorough.
My understanding (very vague) is if that something were as far out as the Oort cloud, it would have to be extremely masssive to account for the Neptune irregularities. And that raises (to me) the further question: if it's that big, how come its gravity hasn't been great enough that the its core heat, generated by gravitational collapse, triggered nuclear fusion -- so that the body would be become a star (and thus visible), rather than a planet?
Seem unlikely to me. My conclusion is that the guy featured in the Discover article is a squirrel. Reading between the lines of the comments of other astronomers quoted in that aritcle, it appears that they share my conclusion. I notice that the featured astronomer is working on this solely "on the side"; no one's interested enough to be funding him.
Max, my understanding (again, per Asimov) is that it's believed that Jupiter itself is just about at the brink of the size above which nuclear fusion would be triggered. (There is rough evidence than Jupiter itself is a bit hotter than such an object would be if non-nuclear, thus suggesting a small amount of nuclear activity at the planet's core). And the Discover article hypothesizes an object roughly 10 times as massive as Jupiter. Raising the question: if so, why no nuclear ignition? (I ask that as a layman, of course.)
As to your point about any known planets orbiting other stars, my answer is very straightforward: I don't know. Let's see if either of us can find anything with a little LIU, as to their size and how their existence was seen or inferred.
tsuwm, granted that Asimov is dead; my point is that the article in essence provided no new science beyond what Asimov wrote some time ago.
tsuwm, I don't see any real changes; just the same old speculation. BTW, Max, you don't need anyone to "gist" the article; your link gives 100% of the text in the printed magazine.
Max, I'm professing ignorance, not scepticism. No doubt extrasolar planets exist (the converse is, statistically, absurd), and I think I recall that some have been detected. I just don't recall anything more about those that were detected. (dumb ignorant -e)
But to make this a word-post: if "solar" is limited to our star, and not to stars generally, what do you call a planetary system around another star? Is there any term less cumbersome than "extrasolar system"?
Well, you do learn something every day: I'd thought that the closest star to our solar system was Alpha Centauri, but apparently it is actually Proxima Centauri. Wordwind, two sites I checked listed the closest star to our planet as the sun, so yes, you're right (not that I doubted it).
And, a system of planets orbiting a star is a solar system. Just not our solar system.
Neptune's rotational axis is reasonably near-horizonal: that is, it lies much closer to the plane of the planet's orbit than is the case with any other planet of our system.
Also, it uniquely rotates "in the wrong direction", when compared with the other planets.
A distinction as to Sirius -- it is the brightest star in our sky (apart from the very occasional supernova), but not the most luminous. That is, others cast off more light, but Sirius appears brightest to us because it is far closer to us than those more-luminous stars (and is far more luminous than the closer stars). In technical terms, it has the greatest magnitude but not the greatest absolute magnitude.
another bit of astronomical trivia, this time word-related:
Which of the major bodies in the (our) solar system have names that are not taken from classical greek or roman mythology? (I say "major bodies" to exclude asteroids -- which are so numerous that we've long since abandoned classical names -- and comets. Let's take "major" to mean larger than the largest asteroid, Ceres.)
The obvious answers are "earth; moon; sun". There are at least two others.
Ariel and Oberon are both bigger than Ceres, which is 950 km or so. These two moons of Uranus, like many others orbiting that planet, came from Shakespeare.
edited later
Umbriel and Titania are also larger than Ceres. Titania comes from Titan, so that probably doesn't count. Umbriel is from Rape of the Lock, I think.
correct. (I'd forgotten Oberon) The pairing of Ariel and Unbriel (light and dark) is rather neat, is it not? Help me out, TEd: aren't they moons of the same planet, which were discovered and named together as a pair? (too lazy to LIU)
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