January 17, By Adrian West, Universe Today. Sirius is the brightest star in the sky and can easily be found in the faint constellation of Canis Major to the left and below Orion.
As seen with the naked eye, Sirius can be seen to twinkle many different colors low in the winter evening sky. This causes the light to slightly bend or shimmer and the light from distant stars twinkle. An extreme, more down-to-Earth example of this would be heat rising off of a road or a desert causing objects behind it to distort, shimmer and change colour. Sirius appears to twinkle or shimmer more than other stars for some very simple reasons.
It is very bright, which can amplify atmospheric effects and it is also very low down in the atmosphere for those in the northern hemisphere.
We are actually looking at it through a very dense part of the atmosphere which can be turbulent and contain many different particles and dust.
The lower towards the horizon an observer is looking, the thicker the atmosphere. The higher an observer is looking, the thinner the atmosphere. This is also the cause of colourful sunrise and sunsets. Phil Plait, the Bad Astronomer explains it very well on his website.
This optical illusion is a big pain for astronomers and some very large telescopes such as those in Chile and Hawaii use special equipment and techniques to reduce the effects of the atmosphere. Twinkle, twinkle little star, now we know what you are and why you are twinkling! Explore further. More from Astronomy and Astrophysics. Use this form if you have come across a typo, inaccuracy or would like to send an edit request for the content on this page.
Typically, the only objects that outshine Sirius in our night sky are the sun, moon, Venus, Jupiter, Mars, and sometimes Mercury. Eventually, the distance between Earth and Sirius will increase. Sirus will become fainter but will remain the brightest star in the sky for thousands of years. Sirius is in the constellation Canis Major, a southern constellation bordering on Monoceros, Lepus, Columba, and Puppis. From mid-northern latitudes, Canis Major sits low in the sky and can be difficult to observe in its entirety.
Sirius also forms the Winter Hexagon or Winter Circle asterism, which appears prominently in the northern sky between December and March and is also part of the Winter Triangle. It's so dim, and therefore so difficult to see from Earth, that astronomers couldn't estimate its mass until , thanks to data from the Hubble Space Telescope.
Sirius is highly visible in the Northern Hemisphere's winter night sky, because the star has a high luminosity , or intrinsic brightness, relativeto other stars, and because it's relatively close to Earth 8.
If the star were placed next to our sun, Sirius would outshine it more than 20 times over. To find Sirius, use the belt of Orion as a pointer. The belt's three stars point downward toward Sirius to the left. To be more precise, the position of Sirius is:. Today, Sirius is nicknamed the "Dog Star" because it is part of the constellation Canis Major, Latin for "the greater dog.
The ancients felt that the combination of the sun during the day and the star at night was responsible for the extreme heat during mid-summer. The star is present in ancient astronomical records of the Greeks, Polynesians and several other cultures. The Egyptians even went so far as to base their calendar on when Sirius was first visible in the eastern sky, shortly before sunrise. By: Alan MacRobert November 12, Save Dark Skies.
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