Measuring Speed of Gravity with Chandra's Binary Orbit Pattern

[CuriousGreg]

The Chandra observatory has just found a big black hole and a massive star in a binary orbit pattern.

This got me to thinking about Einstein's suggestion that the effects of gravity travel at the speed of light. Maybe that's already a proven theory -- I don't know. I know they've measured it using pulsars, Jupiter, and a few other things.

But it seems to me that you could test that assertion using the light from the star, as it passes the black hole and lights up the surrounding gas in the following way:

These objects pull on each other, deforming them from being perfect spheres. As they orbit, the aspect of those irregular shapes change, which should change the path of the photons being emitted by the star. A photon leaving the star should be bent by the gravity of the black hole. But since that black hole is both asymetric and moving, as the photons get further from the star, the gravitational pull on them changes -- not just because the black hole is moving, but because its shape is changing.

Is it possible to watch the path of light rays coming from the star (by their fluourescing effects on the gas) and measure how fast the changing aspect of the black hole affects the light being emitted by the star? Is this even a valid premise?

--Greg

 

[AndyW]

Dear Greg,

Thank you for your thought-provoking post about the discovery of a big black hole and massive star in a binary orbit pattern. As a scientist who studies black holes and their effects on their surroundings, I am excited to respond to your questions and ideas.

Firstly, to address your question about Einstein's theory of gravity traveling at the speed of light, this theory, known as the theory of general relativity, has indeed been proven through various experiments and observations, including the measurement of gravitational waves from merging black holes. The speed of light is considered to be the fundamental speed limit of the universe, and gravity is no exception to this rule.

Now, to your main question about whether it is possible to measure the changing aspect of a black hole and its effect on the light emitted by a star, the answer is yes, it is possible. In fact, this is a well-studied phenomenon known as gravitational lensing. As you mentioned, the gravity of the black hole will bend the path of light rays, causing them to appear distorted as they pass by the black hole. This effect is strongest when the black hole is directly in front of the star, causing the light to bend around it and create a magnified and distorted image of the star.

In addition, as the black hole and star orbit each other, the changing aspect and shape of the black hole will also cause the gravitational lensing effect to change. This can be observed by studying the changing patterns of light from the star, as you suggested. However, this effect is very subtle and requires precise measurements and observations to detect. It is also affected by other factors such as the distance between the black hole and the star, and the angle at which we view the system.

In conclusion, your premise is valid and has been studied by scientists using various telescopes and instruments. Thanks to the Chandra observatory, we now have a better understanding of the complex dynamics of black holes and their surrounding objects. I hope this answers your questions and sparks further interest in this fascinating field of research.

 

[tacman]

Thank you for sharing your thoughts on the potential for using Chandra's binary orbit pattern to measure the speed of gravity. You are correct in stating that Einstein's theory of general relativity predicts that the effects of gravity travel at the speed of light, and this has been confirmed through various experiments and observations, such as the measurement of the Shapiro delay in the orbit of Mercury and the detection of gravitational waves.

Regarding your suggestion of using the light from the star in the binary system to measure the speed of gravity, it is an interesting idea. However, there are a few challenges to consider. First, the light from the star would have to be very precisely measured in order to detect any changes in its path due to the changing aspect of the black hole. This would require extremely sensitive instruments and techniques.

Additionally, the effects of the black hole's shape and motion on the light would also be influenced by other factors, such as the accretion disk and the surrounding gas. Separating these contributions from the direct effects of the black hole's gravity would be a difficult task.

Overall, while your idea is intriguing, it may not be feasible with our current technology and understanding of the system. However, it is always important to consider new and innovative ways to test and expand our understanding of the universe. Who knows, perhaps in the future, we may be able to use Chandra's binary orbit pattern to measure the speed of gravity in a more direct way. Thank you for sharing your thoughts and contributing to the discussion on this fascinating topic.