The Spin of a Star Reveals Its Age 67
eldavojohn writes "Some soon-to-be-published research on gyrochronology has yielded a possible method for more accurately determining a star's age. While determining the age of stars in clusters has been done using the patterns of its color and brightness, singular stars are much more difficult. By comparing established age information from clusters and analyzing the spin of stars, the researchers have established a defined relationship between color (mass), spin and age giving them the beginning of a guide of 'stellar clocks.' This was accomplished after four painstaking years of collecting data from 71 single dwarf members of the open cluster NGC6811 and establishing a model using data from Kepler."
How do they know this is remotely valid? (Score:1, Insightful)
Given that astronomy, in its modern form, only goes back a few hundred years at most (and even then, most of the knowledge was obtained within the past century), how can these scientists feel secure measuring events that span billions of years?
Re:Observation, not math, is what's important. (Score:4, Insightful)
Age can be measured as a consequence of physical behaviour of stars. The difficulty is only knowing exactly which quantities to combine to get the best estimate.
I won't comment on your other ignorant claim that we can't witness the birth of stars today.
Re:Calculations are not direct observations. (Score:5, Insightful)
Here's how science works (as it applies to astronomy):
- You form a hypothesis. In the case of astronomy this would most likely be a concrete mathematical model.
- Your model has predictions which you test.
- If the predictions are valid you look for more ways of testing the model. If not, you scratch it.
Observing the creation and death of one star is *not* necessary to test these models. There are an astronomical(!) number of stars to observe. You have plenty of stars in different stages of development to test the model with.
Certainly the model could be wrong, even if the data are consistent with it, but that does not make it unscientific.
Re:How do they know this is remotely valid? (Score:5, Insightful)
If you took photos of billions of people - but only one per person - could you get a decent idea of how humans age? Same with stars there's roughly 10,000,000,000,000,000,000,000 of them and there's many in every phase of life even though we pretty much only see a snapshot of each one. Take supernovas for example, a very short and rare event we haven't seen since 1604 in the Milky Way even though it has 200-400 billion stars. And yet we find 2-500 of them each year because there's so insanely many galaxies to look at. We won't have observed one star birth to death, but we will have observed everything from baby stars to stars in death throes many, many times.
Re:Observation, not math, is what's important. (Score:5, Insightful)
You are still missing the point. Much of what we consider to be "modern" science is still a house of cards which is not built on a known quantity.
Such as? I can think of string theory (a large unknown with no testable predictions and thus not used for any real science as of yet), dark matter (though we can observe the effects so we know it to be there, they just don't know what it is yet. Lots of very bad theories coming out of this one. I can say that because all but one of them is wrong, and we might not even have the one yet!), and dark energy (which recently got a big boost in observational evidence!)
In the classical scientific method, you have to have a known value that has been verified to be true.
No. Not always. The periodic table of elements was envisioned before there was enough evidence to prove that model correct. Ditto for gravity, "germs", electricity, relativity (general and special), and quantum physics. Those models predicted things that had yet to be observed based on mathematics and known quantities. Their predictions have been tested and proven right. Theories that were wrong are less remembered because they were wrong and abandoned. Steady state, for example.
Mathematical models are not an adequate replacement for known values derived from direct observation.
No, they compliment them. Models predict, observations confirm or contradict. Some models work well only sometimes, like gravity, but within their realm of usefulness they advance science to the point that they break down and science happens all over again. Constant testing and verification. This, just like every other useful model, will be tested mercilessly.
If you think that math and science are strange bedfellows then I encourage you to attempt science without mathematical models. I just don't see how a lack of modeling is an advantage. Clarify if you are willing, but I'm just not seeing it. Mathematics have become more important and much more the focus but it works and it has worked well. Saying that the models don't yield observable quantities nor come from observable quantities is just wrong. Some models take decades. DECADES (I can't stress this enough. Some of Einsteins predictions are still being tested today that have never been tested before such as frame dragging) before their predictions are testable let alone proven.