Twinkle

Twinkle, Twinkle (really fast!), Little Star
The Rossi X-ray Timing Explorer (RXTE) has discovered neutron stars that emit streams of X-rays pulsing over 1,000 times a second.

WHY DO STARS TWINKLE?
Twinkle, twinkle, little star,
How I wonder ...
The scientific name for the twinkling of stars is stellar scintillation (or astronomical scintillation).

Why do stars twinkle?
Answer:
On a clear, dark night, our eyes can see about 6,000 or so stars in the sky. They seem to twinkle, or change their brightness, all the time. In fact, most of the stars are shining with a steady light.

Twinkle, twinkle, little star.
How I wonder what you are.
What is a star?
A star is a big ball of gas. It is not star-shaped. Stars give off heat and light.

Twinkle, twinkle little star: the need for adaptive optics in optical astronomy is a set of slides. The treatment gets very mathematical in places but the information is clear and accessible.
Questions ...

Stars twinkle because we are viewing them through thick layers of turbulent air in the Earth's atmosphere that slightly distort our view. The closer the star is to the horizon the more it appears to twinkle.

In the Twinkle of an EyeIn the Valley of Dying StarsIn the Volume of the Book
In the Wake of DeterminationIn the Wake of PoseidonIn the Wake of the Bounty ...

8. Stars twinkle when we see them because their light is distorted by the Earth's _______________________ .
9. What is the name of a groups of up to about 1,000 stars? ______________________ ...

His eyen twinkled in his head aright, As do the stars in the frosty night. Chaucer.
⇒ The stars are distinguished as planets, and fixed stars. See Planet, Fixed stars under Fixed, and Magnitude of a star under Magnitude.
2.

Nursery rhyme Twinkle twinkle little star
Stars and planetary systems in fiction
Stars in astrology
References ...

The stars that 'twinkle, twinkle' in the night sky are just a few of the countless trillions of glowing orbs that illuminate the universe. Stars come in many sizes, colors, and ages.

Because of its brilliance, Sirius is the champion of all twinklers, the effect caused by variable refraction in the Earth's atmosphere.

When looking at the planetary nebula NGC 6826 it seems to twinkle. When looking at it or away from it seems to blink on and off. This feature gave it the nickname the Blinking Nebula.

White stars (Types B and A) twinkle most; yellow stars (Types F to K) slightly less, and red stars (Type M) least of all.

[20] Due to its brightness, Sirius would have been noted to twinkle more in the unsettled weather conditions of early summer. To Greek observers, this signified certain emanations which caused its malign influence.

The many layers and pockets of air above us are in constant motion and the resulting jiggling of the atmosphere not only makes stars twinkle, but also makes the images we see of all celestial objects look fuzzy.

Twinkle, twinkle little star-- How I wonder, what you are.
Teaching about seasons
Space Launches by Cannon--A
Space Launches by Cannon--B
The Southern Pole of the Sky
Do Astrologers use Wrong Positions for Planets?

Why do stars flicker or twinkle?
Why do stars appear to change color?
It's due to turbulence in the atmosphere. It's just like how things look wavy when you look over a hot grill in the summer, only on a smaller scale.

Why do stars seem to twinkle?
The twinkling of stars is caused by instability of our atmosphere. As the starlight passes through the atmosphere, the movement of the air bends the light slightly and makes the stars twinkle.

That's why stars twinkle and images blur and dance when viewed with telescopes or binoculars. This effect worsens as the zenith angle increases.

When you look at the stars at night you can see them twinkle. This is the effect of layers of air at different temperatures, in the atmosphere, bending light towards and away from your eyes.

The atmospheric turbulence makes the stars twinkle. It also scatters light, more on the blue light and less on the red. Thus, blue light cannot travel very far without changing direction in the atmosphere.

What causes stars to twinkle? What would make good seeing?
Even with perfectly clear skies free of human-made pollution, the seeing on Mauna Kea (4177 meters elevation) is much better than at sea level. Why is that?

Remember-As a general rule stars "twinkle", planets don't.
Comets are gaseous iceballs whizzing through the solar system. Asteroids and meteoroids are giant rocks moving through outer space and sometimes,inner space.

Though it is not nearly as bright as Jupiter, it is easy to identify as a planet because it doesn't "twinkle" like the stars do. The rings and the larger satellites are visible with a small astronomical telescope.

All of the above conditions cause starlight to oscillate about the sky, or "twinkle," and blur, thereby causing them to appear larger than they really are.

The brighter planets do not "twinkle"
The stars appear to "twinkle"
The planets are always near the imaginary yearly path of the Sun on the celestial sphere (the ecliptic) ...

Due to their great distance from the Earth, all stars except the Sun appear to the human eye as shining points in the night sky that twinkle because of the effect of the Earth's atmosphere.

Click on an underlined word for more information on that subject.
Spectroscopy
Twinkle, twinkle, little star,
How I wonder what you are?

Stars appear as points in the nighttime sky that twinkle because of the effect of the Earth's atmosphere. The Sun is an exception: it is the only star sufficiently close to Earth to appear as a disc and to provide daylight.

About an hour after dark in early June, the Summer Triangle's bottom star, Altair, twinkles to the lower right of Vega, almost due east. A ruler held at an arm's length spans the gap between these two stars.

Scintillation is what causes the stars to twinkle, which may be appreciated poetically, but usually means the seeing is not that good. Thermal gradients at different elevations in the atmosphere are usually responsible for the quality of the seeing.

For observations from the Earth's surface, turbulence in the Earth's atmosphere causes point sources (such as stars) to be smeared out and twinkle. This is known as seeing.

of an image due to the layer of gases surrounding the surface of Earth. As starlight travels through the atmosphere, pockets of air act like little lenses and bend the light in unpredictable ways. This distortion causes stars to appear to twinkle.

The lander descended onto Titan in 2005.
Today, Saturn's rings and larger satellites can be seen with a small telescope. By the way, it's easy to identify Saturn as a planet because its light is steady. It doesn't twinkle like the stars.