Official "Science News" Thread

[Dubslow]

Originally Posted by Dubslow

I would like to see an article with more actual detail. In my high school AP class we did air resistance -- it's just F v² for a given aerodynamic profile. It is then trivial to subtract it from gravity and solve the resulting differential equation. Therefore, that article is inaccurate; a demonstration of how bad the media is.

http://www.physicsforums.com/showthread.php?t=609259

[Batalov]

Same different day.
Last time the hoopla was about another prodigy who wrote a closed form for the Bernoulli numbers "for the first time", right?

I mean yes, those kids are definitely smarter than the reporters. The reporters should stick to the they know best - whose dress was the worst in a red carpet reception, or what size of rats are running in the New York subway.

[ewmayer]

Got hold of yesterday's San Jose Mercury News local-news section, which has a nice article about the history of the transits. (Only glitch is they say Venus will be "0.07% the size of the sun", which makes no sense either from a radial or areal-ratio perspective - I think they mean "0.7% the diameter"). Says transit tomorrow begins at 3:04pm PDT, will not be completely over by sunset. Also visible (in-progress at sunrise) Wednesday morning over much of Europe, and entire transit visible over much of the Pacific and Asia.

Next one is in 2117, so I think I need to catch this one, on the off chance I won't be around anymore for that one. :) Will set up the 4" scope on the pool deck behind my place around 3pm, probably just leave it out (in the care of the neighbor kids) for the rest of the afternoon.

Edit: The NYT also has a piece on the transit, which oddly has the byline-date 4. June and talks about "today's transit" - I think the link shows the intended posting date of 5. June.

[xilman]

Originally Posted by ewmayer

Will set up the 4" scope on the pool deck behind my place around 3pm, probably just leave it out (in the care of the neighbor kids) for the rest of the afternoon.

Just ensure that the kids don't try to look at the sun directly through the scope and that they do their best to ensure that no-one else tries it.

[ewmayer]

Originally Posted by xilman

Just ensure that the kids don't try to look at the sun directly through the scope and that they do their best to ensure that no-one else tries it.

I set it up with the eyepiece pointing at a piece of paper on the ground beneath it, and give strict instructions to not look through it. Thanks for the reminder, though.

I just hope it clears up by then - rainy day today, which is un-special in your neck of the woods but highly unusual at this time of year for mine.

[Batalov]

Eclipse was a good rehearsal and they instructed everyone to save glasses for the Venus transit watching.

It is very important not to use any sunglasses or the film that the ophthalmologists give you after dilation, or the antistatic wrap from a m/board or a videocard - these are all weak to a ridiculous degree. Welder's filter is good, or those eclipse glasses.

A good advice that is not repeated often enough is to use a binocular to project on a sheet of paper (not to watch directly or even through eclipse glasses!). Let's see if I'd be able to find a link. This one looks good.

[davieddy]

I found the way to the sun
Set the Controls

[ewmayer]

Transit about 3/4 done as I write this - just put away my 4" scope annd misc. accessories a half-hour ago. Had excellent view using low-mag eyepiece projection onto a white piece of cardboard angled to cut the eyepiece-projected cone of light at 90 degrees. The black dot of Venus starkly silhouetted, also 4-5 easily visible sunspots.

Originally Posted by ewmayer

Only glitch is they say Venus will be "0.07% the size of the sun", which makes no sense either from a radial or areal-ratio perspective - I think they mean "0.7% the diameter"

Neither of these is correct - my 0.7% guess-at-the-typo was based on the ratio of diameters Venus/Sun, but neglected the crucial fact that Venus is much closer to Earth currently than the Sun, which makes its angular diameter relatively larger. Using a ruler (I only had an inch ruler handy), I measured the diameter of the projected Sun on the paper at 3.5", that of Venus around 3/32", which corresponds to a ratio of ~2.7%. The corresponding areal ratio is ~0.07%, so that must be what the above article referred to imprecisely as "size".

Compare that with what one would expect based on measured diameters and distance from-earth -- note that neither the orbit of Venus or earth is sufficiently noncircular to worry about where each is w.r.to its perihelion/aphelion (Earth's orbit is the more eccentric of the two, fwiw), and computations rounded to around the nearest 1%:

Venus: radius =   6,000 km, avg. orbital radius = 108,000 km
Sun  : radius = 696,000 km, avg. distance from earth = 150,000 km

So the diametral ratio Venus/Sun = 6/696 ~= 0.062%, but since the Sun is ~150/32 ~= 4.7x farther from Earth than is Venus, we multiply the two together to get an apparent ratio ~= 4.0%, slightly more than I measured, but diffraction/atmospherics and operator error could certainly account for most of that (although I would think those would make the apparent size of venus larger rather than smaller), and the neglected orbital details could amount for appreciable variance, as well.

Did anybody else here catch it 'Live"?

[Batalov]

Yes

[davieddy]

Don't let the sun go down on me

[davieddy]

Originally Posted by Batalov

Yes

Please don't take this the wrong way:
Lady in Red

David

Back at ya - Lunchtime in LA Never cared for the text only videos anyway...