SoylentNews is people
SoylentNews
The BBC has a report that evidence has been found in lunar rock samples of a planetismal (called Theia) that was thought to have crashed into the Earth to form the Moon. The conclusion is based on a difference in oxygen isotope ratios detected in lunar rock samples returned from the Apollo space missions versus terrestrial samples.
The report is published in the journal Science [abstract]; report is paywalled.
This discussion has been archived.
No new comments can be posted.
Evidence Of Planet That Formed Moon May have been Found In Rock Samples
|
Log In/Create an Account
| Top
| 13 comments
| Search Discussion
The Fine Print: The following comments are owned by whoever posted them. We are not responsible for them in any way.
This login session: $13.76, but for you $11.88.
(Score: 3, Informative) by DrMag on Friday June 06 2014, @07:16PM
Keep in mind, though, what is actually meant by the word theory. Colloquially, it's usually interpreted as a synonym for hypothesis, but that's not the traditional definition. Scientifically, theory means a collection of concepts that brought together explain a particular phenomenon. Relativity, evolution, quantum mechanics, electrodynamics--these are all theories. That doesn't mean they're not well understood or are controversial (though it doesn't necessarily imply the antithesis either). Similarly, in science parlance, a "law" doesn't mean "that's the way it is", it just means we have a mathematical equation that describes a particular observation. "Newton's law of gravity" is wrong; very useful, but wrong. "Law" should never be conflated with truth, as that's not the intent of scientific law, just as "theory" should not be equated with "guess". A theory will be made of a number of hypothesis, observations, and laws. The three parts should be self-consistent, and also be testable.
The word theory is also used in many other fields, including art and music. I suspect the mix-up in definitions came from well-meaning people (many of whom were probably even scientists) who didn't really understand the scientific method. A quick dictionary look-up [reference.com] shows 4/5 definitions match what I'm describing--the other probably has become generally accepted because that's what happens in language; people start using a word wrong, and eventually the definition is adjusted to reflect common usage.
As for asteroids, in the absence of other bodies you're probably correct. It's surprising how much influence the various planets in a solar system can have on things, though, and with all the gravitational perturbations that are present, you might find that, at best, an asteroid becomes "round-ish" if sufficiently fluid, and not just in the oblate spheroid sense like the Earth is.