Where does this come from, and can I check it?

A star's tiny back and forth motion shifts its spectral lines. The figure is taken from NASA Science, which is linked in full on this page. Every fact on Mondo Knows names its source rather than repeating an unsourced claim.

Is this really a space fact?

Yes. It sits on the Space shelf, one of 2,600 sourced facts grouped into space, animals, the human body, history, science and more. Category pages collect every fact in the same field.

What else can I read about it?

The links under the fact point to a quiz, game, puzzle or calculator on the same subject, and the shelf below shows related facts. The wording here is original, and quoted phrases are marked as quotations.

Mondo Knows Facts

Wobbling starlight reveals unseen planets

A star's tiny back and forth motion shifts its spectral lines A planet and its star orbit a shared centre of mass, so the star moves too. That motion changes the wavelength of its light by a tiny Doppler shift, measured as lines sliding in the spectrum. Modern spectrographs resolve speeds near one metre per second, enough to catch an Earth-mass planet around a quiet star. It sits in Mondo's space collection, one of 200 facts that each trace back to the reference below.

Where this comes from

NASA Science

Facts that can change over time are reviewed and updated. If something here looks wrong, Mondo would rather know than be confidently incorrect.

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Space & Astronomy trivia Science trivia

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Splitting starlight reveals what a star is made ofEach element leaves dark lines at fixed wavelengths Some planets orbit two suns at onceKepler-16b circles a pair of stars that also eclipse each other Rogue planets wander the galaxy without a starGravitational scattering can fling worlds into interstellar space on their own TRAPPIST-1 hosts seven Earth-sized rocky planets around an ultracool starThree planets in the system orbit within the habitable liquid water zone The Kepler Space Telescope discovered thousands of exoplanetsMonitoring star brightness dips revealed worlds orbiting distant stars A planet crossing its star dims the lightThe size of the dip gives the planet's radius compared with its star's

Tags: exoplanets, doppler, spectroscopy

Wobbling starlight reveals unseen planets: the short answers

Where does this come from, and can I check it?: A star's tiny back and forth motion shifts its spectral lines. The figure is taken from NASA Science, which is linked in full on this page. Every fact on Mondo Knows names its source rather than repeating an unsourced claim.
Is this really a space fact?: Yes. It sits on the Space shelf, one of 2,600 sourced facts grouped into space, animals, the human body, history, science and more. Category pages collect every fact in the same field.
What else can I read about it?: The links under the fact point to a quiz, game, puzzle or calculator on the same subject, and the shelf below shows related facts. The wording here is original, and quoted phrases are marked as quotations.