Why stars twinkle in the sky

Queen guitarist Brian May and David Eicher launch new astronomy book. Last chance to join our Costa Rica Star Party! Learn about the Moon in a great new book New book chronicles the space program. Dave's Universe Year of Pluto. Groups Why Join? Astronomy Day. The Complete Star Atlas. But through binoculars, a few dimmer stars in the same field appeared steady.

The behavior continued throughout the night, but not a couple of nights later. Allan Hawkinson Carlsbad, New Mexico. Stars scintillate, or twinkle, more or less based on a few factors. This phenomenon, also called scintillation, tends to occur more obviously in bright stars. Snapshot : ALMA spots moon-forming disk around distant exoplanet.

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Sky This Month : November Chiricahua Astronomy Complex: An observing mecca for amateurs. Neutron stars: A cosmic gold mine. Ask Astro : Can a black hole form without a parent star? Cosmos: Origin and Fate of the Universe. Home Science Why do stars twinkle? Some stars appear to flicker between different colours as their light is distorted by our atmosphere, as this composite image of Rigel, Betelgeuse and Sirius shows.

Here, the differences in colour are picked up by a DSLR camera. Credit: Amanda Cross. As incoming cold fronts replace warmer air, they create convection currents that can cause seeing conditions to rapidly deteriorate. A panorama showing the Milky Way centre and planets. Mars is bright to the left, Saturn is dimmer and bright Jupiter is right.

As light travels through the blanket of air around our planet, it is diffracted bounced around causing a quick apparent dimming and brightening — a star's signature "twinkle".

While some stars do physically change in brightness over time, they typically do so on long timescales — amateur astronomers monitor these changes sometimes over hours, but more often over days, weeks, or years.

These variable stars are well studied and often signal complex physical changes happening to the stars in question. The more rapid changes of scintillation, on the other hand, come about long after the light has left the star. Unlike stars, planets don't twinkle. Stars are so distant that they appear as pinpoints of light in the night sky, even when viewed through a telescope. Because all the light is coming from a single point, its path is highly susceptible to atmospheric interference i.

The much closer planets appear instead as tiny disks in the sky a distinction more easily discerned with a telescope than with the naked eye. Their apparent sizes are usually larger than the pockets of air that would distort their light, so the diffractions cancel out and the effects of astronomical scintillation are negligible. Star wheels will help you find your way among the twinkling constellations, and you can trace the appearance of the planets along the ecliptic with a Skygazer's Almanac.

I had a random thought, maybe someone out there has a better idea. Another reason stars twinkle might be because of objects traveling in the lights path. With this sort of occurance happening randomly every minute, every second.