4 ms·

I think of in terms of the data we collect. Make a single measurement over a range of energies/wavelengths/frequencies and you have collected a spectrum. Repeat

by wycx 10y ago

I think of in terms of the data we collect. Make a single measurement over a range of energies/wavelengths/frequencies and you have collected a spectrum. Repeat that measurement or make measurements covering different energies/wavelengths/frequencies and you have some spectra. For the star from the article, I think it is fair to say that Pu consistently appears in the spectra that have been collected.

Stratoscope 10y ago
Thanks, that's an interesting way to look at it and makes complete sense to me. At the risk of sounding like a total nitpicker, I am still a bit confused. I understand that you may measure the star's spectrum and get one result, and I may measure it and get a different result, so now we have two different (but hopefully fairly similar!) spectra for the star. But does this mean that the star itself now has two different spectra? Or is it just that we've both measured it imperfectly and came out with different results? As another example, suppose we have an object with a mass of exactly one gram. I measure it as 0.9999999 grams. You measure it as 1.0000001 grams. Now we have two different masses for the object. Does that mean that the object itself now has two different masses (plural)? Or does it still has a single true mass of its own and we've both just suffered from experimental error? I hope anyone reading this is not too annoyed - I'm just trying to understand how singular and plural work here, and to have some fun with the discussion. :-)
- mirimir 10y ago
  Scientists typically talk about measurements, observations, estimates, etc. Also, spectra of stars are in constant change, so it's not just experimental error.
- thaumasiotes 10y ago
  > I'm just trying to understand how singular and plural work here, and to have some fun with the discussion. Hey, that's my kind of discussion :) There is no one "how singular and plural work here". Singular and plural inflections are a tool speakers can use to express a dimension of their thought; syntax isn't capable of fully determining which will appear. Consider the sentence "my family are all Buddhists". "Family", the subject of the sentence, is unambiguously a singular noun, with plural form "families". The verb in the sentence is, also unambiguously, inflected for a plural subject. It's inflected that way because the speaker wishes, for purposes of the sentence, to conceive of their family as a collection of several people. In another context, it would be unsurprising to see "family" with singular verb agreement. People may say "spectrum" or "spectra" based on what about the situation they're describing they want to provide focus on.
  - Stratoscope 10y ago
    Many thanks to you as well as wycx, cperciva, and mirimir for engaging in the conversation. I learned a few things from you all! I must confess: after my initial comment started gathering downvotes I was on the verge of deleting it. I'm glad I didn't, since it led to such an interesting and informative discussion. I've seen this fairly often on HN, where someone posts a comment that is either factually wrong, off topic, or just something I strongly disagree with, and then a very interesting conversation follows from that. I make a point of upvoting the original comment along with the replies, since after all it was that comment that sparked the discussion.

by wycx 10y ago

Stratoscope 10y ago

Thanks, that's an interesting way to look at it and makes complete sense to me. At the risk of sounding like a total nitpicker, I am still a bit confused. I understand that you may measure the star's spectrum and get one result, and I may measure it and get a different result, so now we have two different (but hopefully fairly similar!) spectra for the star. But does this mean that the star itself now has two different spectra? Or is it just that we've both measured it imperfectly and came out with different results? As another example, suppose we have an object with a mass of exactly one gram. I measure it as 0.9999999 grams. You measure it as 1.0000001 grams. Now we have two different masses for the object. Does that mean that the object itself now has two different masses (plural)? Or does it still has a single true mass of its own and we've both just suffered from experimental error? I hope anyone reading this is not too annoyed - I'm just trying to understand how singular and plural work here, and to have some fun with the discussion. :-)

mirimir 10y ago
Scientists typically talk about measurements, observations, estimates, etc. Also, spectra of stars are in constant change, so it's not just experimental error.
thaumasiotes 10y ago
> I'm just trying to understand how singular and plural work here, and to have some fun with the discussion. Hey, that's my kind of discussion :) There is no one "how singular and plural work here". Singular and plural inflections are a tool speakers can use to express a dimension of their thought; syntax isn't capable of fully determining which will appear. Consider the sentence "my family are all Buddhists". "Family", the subject of the sentence, is unambiguously a singular noun, with plural form "families". The verb in the sentence is, also unambiguously, inflected for a plural subject. It's inflected that way because the speaker wishes, for purposes of the sentence, to conceive of their family as a collection of several people. In another context, it would be unsurprising to see "family" with singular verb agreement. People may say "spectrum" or "spectra" based on what about the situation they're describing they want to provide focus on.
- Stratoscope 10y ago
  Many thanks to you as well as wycx, cperciva, and mirimir for engaging in the conversation. I learned a few things from you all! I must confess: after my initial comment started gathering downvotes I was on the verge of deleting it. I'm glad I didn't, since it led to such an interesting and informative discussion. I've seen this fairly often on HN, where someone posts a comment that is either factually wrong, off topic, or just something I strongly disagree with, and then a very interesting conversation follows from that. I make a point of upvoting the original comment along with the replies, since after all it was that comment that sparked the discussion.