Gravitational waves are predicted but undetectable
Not wrong, but our understanding became significantly more precise.
TaughtEinstein predicted ripples in spacetime, but they are so faint that detecting one is probably beyond any instrument we could build.
NowLIGO detected gravitational waves from two merging black holes on 14 September 2015, announced in February 2016. Detections are now routine, with hundreds recorded.
What actually happened
Einstein predicted gravitational waves in 1916 and then spent years doubting they were physically real rather than a mathematical artifact. The engineering problem is genuinely absurd: the first detected wave stretched and squeezed LIGO's 4-kilometer arms by about one ten-thousandth the width of a proton.
LIGO does it by splitting a laser beam down two perpendicular arms and recombining it. A passing wave changes the relative arm lengths by a fantastically small amount, shifting the interference pattern. The 2015 event, GW150914, came from two black holes of about 36 and 29 solar masses merging 1.3 billion light-years away, converting roughly three solar masses into gravitational energy in a fraction of a second. Rainer Weiss, Barry Barish, and Kip Thorne shared the 2017 Nobel Prize.
In 2017 a neutron star merger was seen in both gravitational waves and light, which opened multi-messenger astronomy and confirmed that such mergers forge heavy elements including gold. Astronomy stopped being purely an observational science that only receives light.
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Sources
- LIGO: Observation of gravitational wavesligo.caltech.edu
- The Nobel Prize in Physics 2017nobelprize.org
Who was taught this
Still standard through 2016, so anyone who finished school between 1950 and 2016 learned the earlier version.