What We (Don't) Know About Dark Matter

The video explores the concept of dark matter, which constitutes 84% of the universe's matter. Initially a catchall term, dark matter is now a specific focus of study due to its gravitational effects on galaxies. Despite extensive evidence, its composition remains unknown. Theories range from modified gravity (MOND) to new particles like WIMPs and axions. Old physics suggests MACHOs and neutrinos, but these lack sufficient evidence. New physics explores supersymmetry and parallel universes, yet no direct evidence supports these ideas. The video concludes with a book promotion on cosmic mysteries.

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