The moon is 3476Km in diameter
Jupiter is 142,984Km in diameter
142984 / 3476 = 41.1346
So Jupiter is 41 times the size of the moon.
The moon is an average of 384,403 Km from Earth
If Jupiter was the same distance from Earth, it would appear 41 times the size of the moon.
Now let's say Elenin is the exact same size as Jupiter... 41 times the size of the moon.
At it's closest distance, Elenin will be 0.232 AU (34,706,706Km) from Earth.
34706706 / 384403 = 90.2873 so its closest distance to Earth will be 90 times the distance the moon is.
At the same distance as the moon, it would be 41 times the size of the moon... but at 90 times the distance, (41 / 90 = .4555) it will appear just less than 1/2 the size of the moon.
On June 29, Elenin was 1.781 AU (266,433,808Km) from Earth.
266,433,808 / 384,403 = 693 On Jun 29th, Elenin was 693 times as far away from Earth as the moon typically is, (41 / 693 = .0592) so it would appear about .06 percent (1/16) the size of the moon.
I'm not sure how that compares to arcseconds, but my Elenin diameter came up a lot smaller than your's did. Is my logic wrong?
Also, I ran across a web page that says a brown dwarf is only slightly above absolute zero, therefore it takes a special low temperature infrared telescope to see one. They claim it doesn't bounce light because of the extreme coldness and therefore would only show as a shadow blocking stars behind it.
"The mystery body was seen twice by the infrared satellite as it scanned the northern sky from last January to November, when the satellite ran out of the supercold helium that allowed its telescope to see the coldest bodies in the heavens"
"Whatever it is, Houck said, the mystery body is so cold its temperature is no more than 40 degrees above "absolute" zero, which is 459 degrees Fahrenheit below zero. The telescope aboard IRAS is cooled so low and is so sensitive it can "see" objects in the heavens that are only 20 degrees above absolute zero. When IRAS scientists first saw the mystery body and calculated that it could be as close as 50 billion miles, there was some speculation that it might be moving toward Earth. "It's not incoming mail," Cal Tech's Neugebauer said. "I want to douse that idea with as much cold water as I can."
Obviously Elenin IS incoming... Nasa tracking proves that.
But, if even if a Brown Dwarf is NOT visible at 50 billion miles (538 AU), I would think one would it be visible at 1.7 AU, which is where it is now.
Kevin Heckle (29 June 2011)
"John RP & Luis Vega: 188 days Elenin"
Very good skeptical questions. I am bewildered as to why the Elenin fascination continues. Again, it is a small insignificant commentary object. While it possibly could be perturbed gravitationally by another object (and vice versa) it currently does NOT pose any threat to this world whatsoever. The reason it has no tail as of yet is because of its small size and distance from the sun. I believe it just recently passed the orbit of Mars. For those of you who think that Elenin is a “brown dwarf” making it difficult to see, do not understand the concept of a brown dwarf star. When astronomers express that brown dwarfs are difficult to observe, they are speaking of those that are at great distances outside of our solar system. A brown dwarf is VERY SIMILAR to the planet Jupiter. To be considered a brown dwarf, an object would at least be the size of Jupiter, if not much larger. If Jupiter had been any larger in mass, it may have ignited fusion and became a star. Even though it did not, it is one of the brightest objects in the sky at night BECAUSE IT REFLECTS THE LIGHT OF THE SUN.
Consider this: If Elenin is a brown dwarf, which would make it as least as big as Jupiter, then how come it is not visible? Why would it not reflect light in the same way as Jupiter? Jupiter is 21 times larger in diameter than Mars. IF Elenin, currently at about the orbit of Mars, were at least as big as Jupiter (21 times larger than Mars) it would be currently appearing in the sky as about 1/3rd the size of the moon.
Jupiter = 143000 km diameter, appears to be 50.1 arcseconds in diameter from earth
Mars = 6800km diameter, appears to be 25.1 arcseconds in diameter from earth
143000/6800=21.02 times bigger than Mars would be any smallest ‘brown dwarf’ sized object (like Jupiter).
So if this “brown dwarf” being at least as large as Jupiter is currently as close as Mars, then it would appear as 21.02 times larger than Mars. Mars appears as 25.1 arcseconds in diameter at its closest, so the “brown dwarf” would appear as 21.02 times 25.1 arcseconds, or about 528 arcseconds in diameter. The moon at its closest appears to be about 1900 arcseconds in diameter. So if Elenin were a brown dwarf just now passing Mars, it would appear in the sky to be 27.7% the size of the moon.
If there were something in the sky about a third the size of the moon, we could see it night or day. Go outside wherever you are and scan the sky for something that big. You will not see it, because it DOES NOT EXIST!
We as Christians are not supposed to be the ones deluded. Study to show yourself approved before jumping on the falsehood band wagon! Be a little skeptical about getting your scientific facts from a Youtube video.