简介:【原文】Butlet'sstepbackforasecondhereandexplainwhatgravitationalwavesactuallyare.AccordingtoEinstein'stheory,thefabricofspace-timecanbecomecurvedbyanythingmassiveintheUniverse.Whencataclysmiceventshappen,suchasblackholesmergingorstarsex-ploding,thesecurvescanrippleoutelsewhereasgravitationalwaves,justlikeifsomeonehaddroppedastoneinapond.BythetimethoseripplesgettousonEarth,they'retiny(aroundabillionthofthediam-eterofanatom),whichiswhyscientistshavestruggledforsomanyyearstofindthem.--NewYorkTimes.
简介:Visitingthesaunaregularlycouldreducetheriskofdementia,anewstudyhasfound.ScientistsattheUniversityofEastFinlandfollowedmorethan2,000middle-agedmenfor20yearstofindoutwhatfactorsinfluencedhowmanydevelopedcognitive~1problemsinlaterlife.