The solar system originated from a collapsing cloud of gas and dust approximately 4.5 billion years ago, with the Sun forming in the central region through nuclear fusion and the planets condensing ...

Forbes contributors publish independent expert analyses and insights. Dianne Plummer is an Energy Consultant and Certified Energy Manager. Rooftop solar has become one of the fastest-growing clean ...

Test your knowledge on our solar system, from the biggest and smallest planets to the behemoth mountain on Mars. When you purchase through links on our site, we may earn an affiliate commission.

The solar system is 4.54 billion years old, based on rock dating. Gas giants (Jupiter and Saturn) likely formed first. Ice giants (Uranus and Neptune) probably formed next. Rocky planets formed last, ...