Stellar Aberration

Stellar aberration is the apparent movement of stars as a result of the motion of the Earth. Discovered by James Bradley back in 1727, it is an interesting case of the application of the scientific method. Observations were made to test a scientific theory (the heliocentric theory in which the Earth revolves around the Sun), but unexpected results were found.

These not only proved heliocentric theory but also led to the first accurate measurement of the speed of light.

[Zodiaczero]

Thanks for simple and informative explanation!
I couldn't grasp the idea behind math without the video!

[hajarmouqadem]

This helped me a lot to understand, thanks

[fede_ponz]

thank you very much, you're helping me out with my astronomy course

[venkat]

Thanks for the clear explanation. Really informative.

[mimzim]

How does that much larger effect not messup the parallax measurements? Are those compensated for in parallax calculation?

[johndavies]

great video just the right level of detail for me

[Daz]

Sorry if this is a dumb question, but if we’re looking at the constant motion of a distant star, how can we tell that it’s position is distorted due to aberration? What reference point do we have to determine the ‘true’ position of where the star should be?

[xyzoub]

If stellar aberration does not vary with the distance of the star, how can it be related to light?

[seetharama]

Regarding Water filled Telescope : Consider a star right above head w.r.t. sun. When observed through telescope the telescope should be held at an angle in the direction of motion of earth. we can imagine telescope to have large number of horizontal sections parallel to the direction of motion. Each section of telescope enters path of vertical ray falling from star consecutively. In other words the telescope will have 'Virtual Vertical Tilt'. Therefore, the medium inside the telescope ( whether air or water or any oil or even a glass cylinder will have no bearing except delay in exit of the ray). Regarding effect of motion of solar system around the galaxy. Observation over a small number of years will not reveal any changes as its effect is already got added-up in locating the star. This explanation can be extended to aberration of stars situated at an angle also.

[comicrelief]

There must also be some fluctuation in wavelength, yeah? That is, in the perceived wavelengths of the star's light.

[vimalramachandran]

Great explanation overall. But it wasn't clear how a stationary ether would cause no aberration. If you illustrated that, it would have been easier to understand.

[Aurora_yt]

Is that why sometimes we see stars through the moon?

[timetin]

bradley et al's "velocity of light" explanation is wrong tho

[christophep]

Thank you but if you could leave alone religion. Heliocentrism was not a religion theory but one of the highest philosopher of the Reason Aristotle and a scientific guy Ptoleme. Many scholars didn t see any inconvenience with heliocentrism, expressed it and weren t burned for it. One of the most prominent was Nicolas de Cues a clerk close to the Pope in XV century.
The fact is that Galile found a much better performing system but wasn t able to prove Heliocentrism.

[jackflash]

I've heard that back and forth stellar aberrations cannot be observed for binary star systems, such that the binary star system always seems to look like a single star. Is there a logical explanation for this?

[RayleighCriterion]

The scientific method requires dependant and independent variables.

[youtube_acct_]

How does the Earth's tilt come into this?

[philoso]

Very helpful. Thanks
Earth is speeding around its orbit. Is our sun and the distant object star stationary? If not, the prediction method here may be incomplete?

[kneelingcatholic]

I could have used a little more explanation around 12:00 when you dicussed Airey's failure. He expected to see a different aberration tilt assuming only that:
Light travels slower in water than in the vacuum of space.

This is the same assumption we make today. I don't see what disbelief/belief in ether has anything to do with his experiment.

[stephen]

Very sneaky indeed! 'Frame of reference' is code for aether. I am not fooled! lol!