Re: James Webb Telescope
Posted: December 26th, 2021, 7:35 am
Which moon is it on?NotSure wrote:It is apparently sensitive enough to detect a candle on one of Jupiter's moons!
https://www.ralspace.stfc.ac.uk/Pages/F ... -NASA.aspx
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Which moon is it on?NotSure wrote:It is apparently sensitive enough to detect a candle on one of Jupiter's moons!
https://www.ralspace.stfc.ac.uk/Pages/F ... -NASA.aspx
I'm more concerned about who put it there!MrFoolish wrote:Which moon is it on?NotSure wrote:It is apparently sensitive enough to detect a candle on one of Jupiter's moons!
https://www.ralspace.stfc.ac.uk/Pages/F ... -NASA.aspx
[Spartacus]Mike4 wrote:I'm more concerned about who put it there!MrFoolish wrote: Which moon is it on?
I've no idea (and I suspect your question is rhetorical anyway), but, I ran some quick numbers to see if this claim was even remotely plausible (E&OE).MrFoolish wrote:Which moon is it on?NotSure wrote:It is apparently sensitive enough to detect a candle on one of Jupiter's moons!
https://www.ralspace.stfc.ac.uk/Pages/F ... -NASA.aspx
If it is then something must be providing a fairly high concentration of oxygen in its vicinity.scrumpyjack wrote:Is it alight?
Where do you buy your candles?NotSure wrote: Using round numbers throughout for an 'order or magnitude' estimate, a candle outputs around 100 W.
One of these?GrahamPlatt wrote:Where do you buy your candles?NotSure wrote: Using round numbers throughout for an 'order or magnitude' estimate, a candle outputs around 100 W.
GrahamPlatt wrote:Where do you buy your candles?NotSure wrote: Using round numbers throughout for an 'order or magnitude' estimate, a candle outputs around 100 W.
A standard British candle was made from spermaceti from sperm whales and emitted about 80W. The French were ahead of the game with a vegan alternative.GrahamPlatt wrote:Where do you buy your candles?NotSure wrote: Using round numbers throughout for an 'order or magnitude' estimate, a candle outputs around 100 W.
Shouldn't the sperm whale and a bowl of petunias be on your list too?jfgw wrote:A standard British candle was made from spermaceti from sperm whales and emitted about 80W. The French were ahead of the game with a vegan alternative.GrahamPlatt wrote: Where do you buy your candles?
I didn't realise that Jupiter had so many moons — 79 discovered as of this 2018 article, https://carnegiescience.edu/news/dozen- ... l%E2%80%9D. Io has an atmosphere of, mostly, sulphur dioxide. I don't know about the other moons. It may be possible to formulate a candle that will burn in such an atmosphere (I am not a chemist). Combustion can occur without oxygen, for example, lithium will burn in nitrogen.
I am opening a book as to which the telescope will find first:
4/5 the candle;
1/1 the teapot.
Julian F. G. W.
More likely a McDonalds drink cup, on the basis they turn up in litter everywhere.jfgw wrote:I am opening a book as to which the telescope will find first:
4/5 the candle;
1/1 the teapot
It wouldn't surprise be if they had a branch on one of Jupiter's moons.MrFoolish wrote:More likely a McDonalds drink cup, on the basis they turn up in litter everywhere.jfgw wrote:I am opening a book as to which the telescope will find first:
4/5 the candle;
1/1 the teapot
Ir should be able to spot Bertrand Russell's teapot which is orbiting somewhere between earth and marsjfgw wrote:It wouldn't surprise be if they had a branch on one of Jupiter's moons.MrFoolish wrote: More likely a McDonalds drink cup, on the basis they turn up in litter everywhere.
Julian F. G. W.
The original quote is an overstatement. Webb might detect a candle against a dark background at the distance of Jupiter. It could not resolve a candle on a sunlit Jovian moon. This would be a harder problem than discriminating extra-solar planets near a star.NotSure wrote:I've no idea (and I suspect your question is rhetorical anyway), but, I ran some quick numbers to see if this claim was even remotely plausible (E&OE).MrFoolish wrote: Which moon is it on?
Using round numbers throughout for an 'order or magnitude' estimate, a candle outputs around 100 W. If we assume (for simplicity) that all the power is concentrated the middle of the JW IR band, i.e. at 10 microns, that is around 1e22 photons/s.
Applying the inverse square law, with Jupiter around 600 million km away, and the JW dish of diameter 6.5 m, I make it that 2 or 3 photons/minute could be captured by the JW. So just about plausible with a long exposure and an extremely high SNR?
Party pooper9873210 wrote: The original quote is an overstatement. Webb might detect a candle against a dark background at the distance of Jupiter. It could not resolve a candle on a sunlit Jovian moon......
If that poops your party you need more rocket fuel.NotSure wrote:Party pooper9873210 wrote: The original quote is an overstatement. Webb might detect a candle against a dark background at the distance of Jupiter. It could not resolve a candle on a sunlit Jovian moon......Of couse you'd only try at night!
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Next you'll be pointing out that the candle would be cold anyway as there's no oxygen on Europa (at least not in gaseous form).....
It was probably one of them electric candles, like what Ray Davies sang about in his song "Lola". I guess it would have to be actually, given the oxygen problem.NotSure wrote:Party pooper9873210 wrote: The original quote is an overstatement. Webb might detect a candle against a dark background at the distance of Jupiter. It could not resolve a candle on a sunlit Jovian moon......Of couse you'd only try at night!
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Next you'll be pointing out that the candle would be cold anyway as there's no oxygen on Europa (at least not in gaseous form).....