If it is still a theory.
Then by definition it is NOT finally solved.
Dark energy mystery is finally SOLVED - as scientists come up with a radical new theory to explain the mysterious force | Daily Mail Online
https://www.dailymail.co.uk/sciencetech/article-14214499/Dark-energy-mystery-finally-SOLVED.html
> Scientists have proposed a radical theory to explain the expansion of the universe which could solve the mystery of dark energy.
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