Volunteers Use Annular Eclipse To Measure Sun More Accurately 75
Anonymous Squonk writes "The measurement of the sun currently in use was actually calculated over 120 years ago, and is off by hundreds of kilometers. Thousands of ordinary Japanese citizens worked together to improve this estimate. By measuring the borders of the 'ring of fire' effect of the recent eclipse, and using the known size and distance from the Earth of the sun, the radius of the Sun was measured as 696,010 kilometers, with a margin of error of only 20 kilometers."
Incidentally... (Score:5, Interesting)
I'm told that the 'expands and engulfs the inner planets' stage will be dramatic; but is the expectation before that event a very, very gradual shrinking or something more complex?
Re: (Score:2)
Well, I would assume a gradual expansion.
Since the more reactions happen, the more mass it loses, thus the attraction on the nearby atoms/molecules lessen, thus allowing them to go a bit further away.
Re:Incidentally... (Score:5, Interesting)
Re: (Score:1)
Sunspots go up, sunspots go down..
You can't explain that.
Re: (Score:3)
Answer: Yes. The sun will continue to gradually shrink until it runs out of H to burn.
Actually the opposite is true. Our sun is doomed to end up a red giant and eventually the Earth will be eaten by the sun. It's a middle aged star so there are billions of years to go.
Re:Incidentally... (Score:5, Informative)
Re:Incidentally... (Score:5, Funny)
You had me in a panic there - I thought you said millions.
Re: (Score:2)
Re: (Score:2)
Earth's orbit will increase in radius (without becoming more elliptical) as the Sun's mass decreases, and when the Sun goes red giant, the Earth will vaporize.
Unless, of course, we move the Earth before then.
Re: (Score:2)
Earth's orbit will become more and more elliptical over time and will eventually either slingshot Earth out of the orbit and directly into the Sun.
You can't slingshot unless you have three bodies. Sun, Earth...and what is the third one, larger than Earth, that Earth regularly approaches?
Re: (Score:2)
You can't slingshot unless you have three bodies.
Pardon? How about we think of it as Earth falling into the Sun's gravity well far enough to be accelerated but not far enough to be captured. What happens next? I'd guess Earth gets flung off into the Oort cloud. That sounds like a two body slingshot effect to me.
Re: (Score:2)
Re: (Score:2)
You can't explain that.
Re: (Score:1)
Re:Incidentally... (Score:5, Informative)
The Sun is growing right now and it is getting brighter by the day. This is not occurring at a rapid rate at the present time. It is due to the slow accumulation of helium in the core of the Sun. Helium doesn't undergo fusion at this time (not hot enough). The increase in helium would imply a decrease in the fusion rate, but due to maintaining a hydrostatic equilibrium, the temperature of the core increases and the fusion rate actually increases. This causes the radius to increase.
Re: (Score:1)
Obviously the sun is getting hotter. Haven't you heard of global warming? If we don't do something soon, we'll get completely enveloped by the sun.
Re: (Score:3)
but doing all that mass-energy conversion and indiscriminate radiating must be slowly changing the sun's size
This assumes that the Sun actually *has* a size, in a real, rather than purely mathematical sense. The outer layers of the Sun are a translucent vacuum. A harder vacuum than we were able to achieve for most of the 20th C, glowing like a neon light so that the visibility through those outer layers is about what the old London Pea Soup fogs were like. If we could view it in infrared, the Sun would have a larger "diameter" than this measurement, and of course smaller if measured from its ultraviolet image,
Manned Mission Needed (Score:5, Funny)
I think to get the most accurate measurement, we need to send a manned mission to the sun and do it the old fashioned way, with a tape measure.
Of course, to keep from burning up, they will have to go at night.
Re:Manned Mission Needed (Score:4, Funny)
Or during an eclipse.
Just jump through the Flaming Hoop of Death.... (Score:2)
Your method suggests that extreme accuracy is required.
You don't want to be off-center, otherwise you might singe your tail feathers.....;-)
Re:Manned Mission Needed (Score:4, Funny)
Re: (Score:2)
Or during Winter.. You know this was a yahoo question. http://answers.yahoo.com/question/index?qid=20120430182228AAIk7uw [yahoo.com]
Well, mine was inspired by a quip in an old indy comic back in the late 80s or early 90s called Space Ark. The bit there was:
"How can we get close enough to the sun without burning up?"
"Simple. We go at night."
As for the Yahoo Answers post, I found it hilarious... hilarious that so many people actually thought the OP was being serious instead of seeing it for the silliness that it is.
Re:Manned Mission Needed (Score:5, Funny)
I think to get the most accurate measurement, we need to send a manned mission to the sun and do it the old fashioned way, with a tape measure.
Of course, to keep from burning up, they will have to go at night.
A waste of time and money. The eclipse proved that the sun is only slightly larger than the moon. Now you just have to use a tape measure to get an accurate size for the moon. Too bad the astronauts didn't think to take one.
Re: (Score:2)
If doing it during an eclipse, it may be worthwhile to measure the sun's corona. Even better though would be to measure its Alaskan Amber.
Re:Manned Mission Needed (Score:5, Funny)
Re: (Score:2)
Re: (Score:2)
Who needs astronauts and tape measures when you have Three Wolf Moon [wikipedia.org]? That moon don't look no bigger than a wolfs head, and wolfs we have a'plenty 'round here. Just grab one of 'm, measure its head and viola (sic).
Re: (Score:2)
Just grab one of 'm, measure its head and viola (sic).
Just don't forget that afterward, there is always room for cello.
Wouldn't it be great... (Score:1)
Re: (Score:2)
Re:Wouldn't it be great... (Score:5, Funny)
Wouldn't it be great if people learned foreign languages ? If people would allow foreigners to puplish in their on language ?...
Yeah too much to ask, I guess.
IMO everyone should be allowed to puplish in the language of their choice, so long as they do it in the privacy of their own home.
Re: (Score:2)
Re: (Score:2)
So, how many languages do YOU speak?
Re: (Score:3, Informative)
English language version:
http://ajw.asahi.com/article/behind_news/social_affairs/AJ201205250024 [asahi.com]
Sorry, can't resist. (Score:4, Funny)
That's a relatively open weave and I can still see your... annular area.
Currently in use (Score:4, Funny)
Good to see they focused their research on the sun that's currently in use and not on one of those old disposed ones!
Wasn't this already known? (Score:3, Informative)
NASA seemed to know it's 696,000km long before this experiment [nasa.gov].
Re: (Score:2)
I missed it (Score:4, Funny)
Oh my god (Score:5, Funny)
The measurement of the sun currently in use was actually calculated over 120 years ago, and is off by hundreds of kilometers.
By the best available measurements the sun has shrunk by hundreds of kilometers in a space of 120 years... and in that time is when we've started using solar power. We should stop now while there's still some Sun left.
Re: (Score:1)
We should stop now while there's still some Sun left.
Too late. The remainder of Sun is too busy suing Google...
Define 'Sun' (Score:4, Interesting)
Seriously; it has a atmosphere thousands of miles thick, with a fuzzy, boiling edge..
The margin of error on this is ludicrous.
Plus.. of course, it is continually boiling itself off onto space, so even if you could define a 'hard edge' to it, your measurements would become worthless in, say, a few million years ;-)
Re: (Score:3, Informative)
Not to mention that it's probably not a perfect sphere, so a single radius doesn't capture its size.
Wikipedia sayth:
It is a near-perfect sphere, with an oblateness estimated at about 9 millionths, which means that its polar diameter differs from its equatorial diameter by only 10 km. As the Sun consists of a plasma and is not solid, it rotates faster at its equator than at its poles. This behavior is known as differential rotation, and is caused by convection in the Sun and the movement of mass, due to steep temperature gradients from the core outwards. This mass carries a portion of the Sun’s counter-clockwise angular momentum, as viewed from the ecliptic north pole, thus redistributing the angular velocity. The period of this actual rotation is approximately 25.6 days at the equator and 33.5 days at the poles. However, due to our constantly changing vantage point from the Earth as it orbits the Sun, the apparent rotation of the star at its equator is about 28 days. The centrifugal effect of this slow rotation is 18 million times weaker than the surface gravity at the Sun's equator. The tidal effect of the planets is even weaker, and does not significantly affect the shape of the Sun.
So more round than you might think. :)
Re: (Score:2)
This, it's a cloud of gas and defining its surface based on a given brightness (I guess, since this is an optical measurement) is pretty arbitrary.
How accurate can it be ? (Score:5, Insightful)
Is this not somewhat akin to trying to measure the depth of a saucepan of boiling water ?
Re: (Score:2)
In related news... (Score:2)
Article unintelligible (Score:2)
Re: (Score:2)
Can we get it translated from the original Japanese to English by a person who speaks both languages fluently?
Well, I don't have time to do the whole thing, but here's the gist: </moz-synch-lips> "Oh no Sun-Zilla!"
Measured using known dimensions? (Score:3)
Japanese citizens worked together to improve this estimate. By measuring the borders of the 'ring of fire' effect of the recent eclipse, and using the known size and distance from the Earth of the sun, the radius of the Sun was measured as 696,010 kilometers, with a margin of error of only 20 kilometers."
Wow! That's some breakthrough science!
I'm still sore that it rained where I live (Score:2)
I live in Western Canada, and we were supposed to get as much as 80% coverage of the sun at my location, near sunset. I even managed to secure some solar glasses especially for watching the event. It had been sunny for almost two whole weeks before the event, with barely a cloud in the sky. The eclipse happens and BAM... it's so freakin' overcast and rainy that you can't even tell which way the sun *IS*.
Before sunset the next day, the clouds had cleared, and it's been sunny ever since.
The universe h
Correction Factors? (Score:1)
Whole story is junk (Score:2)
Surely this is no news at all; the Sun has been measured as accurately as possible (given that it doesn't have a well-defined edge) by satellite telemetry long ago. This should perhaps be titled 'most accurate calculation by amateur Japanese without modern equipment' or something