Could a “demon” break one of the most fundamental laws of physics? Maxwell’s demon has puzzled physicists for more than 150 years. What began as a thought experiment about heat and entropy is now part of our understanding of information, computation and the laws of thermodynamics. Physicist John Goold explains the paradox and what the demon reveals about the relationship between entropy, measurement and the quantum world.

Could our universe have more dimensions than the three of space and one of time that we experience?

Recent results from the Dark Energy Spectroscopic Instrument (DESI) have renewed interest in whether our current picture of the universe is complete. Some theories suggest that extra dimensions could help explain three of the greatest mysteries in physics: the nature of dark energy; the invisible influence of dark matter; and why gravity is so much weaker than the other fundamental forces.

From string theory to braneworlds, the search for extra dimensions pushes the boundaries of science and could reveal that the reality we experience isn’t all there is.

In the centre of our galaxy sits a monster 4.3 million times the mass of the sun. But Sagittarius A* is tiny compared with other black holes in the universe, with some reaching up to 40 billion times the mass of the sun. They are the point where our laws of physics break, and how these giants get so big has puzzled scientists for decades.

Becky Smethurst is an astrophysicst at the University of Oxford and her work looks at how these behemoths affect the galaxy around them. New Scientist‘s digital features editor, Jacklin Kwan, sat down with her to discuss what black holes are, how the supermassive ones get so big and Smethurst’s amazing career.