Planetary Composition Quotes

What I want to look at with Webb is what we call ice giants in our solar system - the planets Neptune and Uranus.

When you look at Venus and the Earth, they formed at about the same place in the solar system. They're made of about the same materials; they're about the same size.

The smaller the planets are, they are, other things being equal, of so much the greater density; for so the powers of gravity on their several surfaces come nearer to equality. They are likewise, other things being equal, of the greater density, as they are nearer to the sun.

Generally speaking, exoplanets can be any size, and they are found in a wide range of orbits. Some have massive gas atmospheres; others are smaller with an icy or rocky composition.

Earlier generations of stars in the galaxy could well have had planets. But really, there was only hydrogen and helium to work with, so they'd all be gas giants and not small, rocky planets.

55 Cancri is extraordinarily rich in heavy elements and extraordinarily efficient at making planets - much more so than our sun - and those elements are the very ones you need to make planets that aren't just gas giants.

Astronomers have discovered a planet that is twice the size of earth and made of diamonds. President Obama says the planet may be inhabited by aliens not paying their fair share.

Pluto is as far across as Manhattan to Miami, but its atmosphere is bigger than the Earth's.

Super-Earths are how we call a family of planets... up to two times larger and about ten times more massive than the Earth.

I tell my students, with a feeling of pride that I hope they will share, that the carbon, nitrogen, and oxygen that make up ninety-nine per cent of our living substance were cooked in the deep interiors of earlier generations of dying stars. Gathered up from the ends of the universe, over billions of years, eventually they came to form, in part, the substance of our sun, its planets, and ourselves. Three billion years ago, life arose upon the earth. It is the only life in the solar system.