Physical Forces


Star Power

I have loved the stars too fondly to be fearful of the night.

~ Galileo Galilei

Hubble Observes Infant Stars in Nearby Galaxy (2004)
NASA, ESA and the Hubble Heritage Team (STScI/AURA)-ESA/Hubble Collaboration
Stars enthralled humankind long before the emergence of physics as a science. The names of many constellations attest to their presumed connection to the gods. However, far from being the work of supernatural forces, stars are formed from natural processes. Isaac Newton suggested that gravity was the driving force behind the formation of stars, and research over the last 60 years has supported this claim. When diffuse matter in space, referred to as space dust, begins to contract under its own gravitational force, it begins to collapse into itself.

As the core grows hotter, it eventually achieves nuclear fusion and a star is born. Stars first appeared 100 million years after the Big Bang, bringing light to the infinite darkness of the universe. The power generated by a star can be staggering, especially when collisions between smaller stars produce a much larger one. This type of power is evidenced by the sun, and the first stars were likely many times more massive.


A star flares, vaporizing the atmosphere of a planet (2012). NASA, ESA, L. Calçada