4 ms·
Dark matter has not been observed, hence the name. We know something is there, but we don't know what is is and we have not seen it.
by zzzmarcus 15y ago
Dark matter has not been observed, hence the name. We know something is there, but we don't know what is is and we have not seen it.
- SoftwareMaven 15y agoIts gravitational effects have been observed, that is how we know it is there. Nobody has seen it, but little in the sky is actually accessible via visible wavelengths.
- evgen 15y agoA gravitational anomaly has been observed, but the source of this anomaly is not just invisible to the visible wavelengths but from all wavelengths we can measure. "Dark matter" sounded a bit better than "unicorn turds" I guess, but at the moment each is equally likely.
- gjm11 15y ago> at the moment each is equally likely. Impossible. Unicorn turds would be a variety of dark matter; if most of the apparent mass in the universe were made of unicorn turds, the dark matter hypothesis would be correct. (Unless they were very sparkly unicorn turds, emitting enough light for us to detect from far off.) Further: they'd be a very boring kind of dark matter: the same kind of stuff as we, the earth, the moon, etc., are made of. And there's very good reason already to believe that there isn't enough of that to account for the gravitational anomalies you get if you assume no dark matter. I therefore declare: Pr(anomaly comes from unicorn turds) is much smaller than Pr(anomaly comes from dark matter).
- idlewords 15y agoI guess it depends on your definition of 'seen'. Certainly the evidence is very unambiguous: http://blogs.discovermagazine.com/cosmicvariance/2006/08/21/dark-matter-exists/ http://blogs.discovermagazine.com/cosmicvariance/2006/08/21/...
- teraflop 15y agoNo, it's called "dark matter" because it appears not to interact with electromagnetic radiation but has mass. We can observe it indirectly through its gravitational influence, such as altered galactic rotation curves and weak lensing. (If we hadn't somehow observed it, and we didn't have a theory that predicted it, why would we think it exists at all?) Regardless, the point I was getting at is that confirming or denying the existence of the Higgs boson would have little or no direct impact on our understanding of dark matter. (I'm not a physicist, but this is my layman's understanding of the situation, and I haven't heard any physicists claiming otherwise.)
- wlievens 15y agoI think 'knowing something is there' implies observation. Just not in visible light, or some other pedestrian interpretation of the word :)