Quantum vacuum: Less than zero energy

According to quantum physics, energy can be 'borrowed' — at least for some time. Energies lower than zero are possible, much like a bank account that can be overdrawn. There are, however, certain restrictions to that. Scientists have now shown that these restrictions are very fundamental properties of our universe and must be true for various possible quantum theories.

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Black holes and their host galaxies, growing old together

The 'special relationship' between supermassive black holes (SMBHs) and their hosts — something astronomers and physicists have observed for quite a while — can now be understood as a bond that begins early in a galaxy's formation and has a say in how both the galaxy and the SMBH at its center grow over time, according to a new study.

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Six galaxies undergoing sudden, dramatic transitions

Astronomers observed six mild-mannered LINER galaxies suddenly and surprisingly transforming into ravenous quasars — home to the brightest of all active galactic nuclei. The team's observations could help demystify the nature of both LINERs and quasars while answering some burning questions about galactic evolution. Based on their analysis, the researchers suggest they have discovered an entirely new type of black hole activity at the centers of these six LINER galaxies.

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New hunt for dark matter

Dark matter is only known by its effect on massive astronomical bodies, but has yet to be directly observed or even identified. A theory about what dark matter might be suggests that it could be a particle called an axion and that these could be detectable with laser-based experiments that already exist. These laser experiments are gravitational-wave observatories.

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