• pitbull
In summary: Something nice to understand is e.g. why the massless limit of massive Fierz-Pauli theory does not give the results of linearized GR. This is called the vDVZ discontinuity (van Dam-Veltman-Zakharov). See e.g. the excellent noteshttps://arxiv.org/abs/1105.3735Just my 2 cents ;)In summary, a descriptive thesis that avoids math would be uninteresting, but if you could say something about how GR gives rise to propoagating

#### pitbull

Gold Member
Hey!

I am about to start my Bachelor's thesis about General Relativity. My professor mentioned that my thesis might as well be related to Gravitational Waves. Do you think that it would be appropriate to work on Gravitational Waves for a Bachelor's thesis? Isn't it too advanced?
Also, any idea on what part of Gravitational Waves I could discuss?

Since its for a BS then how about how they traverse spacetime and how LIGO has successfully detected them. Other ideas could be how they are formed and their properties.

https://en.wikipedia.org/wiki/Gravitational_wave

As an aside:

Also one common issue is peoples conflation of gravity waves vs gravitational waves. They are separate phenomena. Here's a link for reference on gravity waves so you can see the difference

https://en.wikipedia.org/wiki/Gravity_wave

pitbull
jedishrfu said:
Since its for a BS then how about how they traverse spacetime and how LIGO has successfully detected them. Other ideas could be how they are formed and their properties.

https://en.wikipedia.org/wiki/Gravitational_wave

As an aside:

Also one common issue is peoples conflation of gravity waves vs gravitational waves. They are separate phenomena. Here's a link for reference on gravity waves so you can see the difference

https://en.wikipedia.org/wiki/Gravity_wave

So this paper is actually about gravitational waves, and not gravity waves, right?

pitbull said:
Hey!

I am about to start my Bachelor's thesis about General Relativity. My professor mentioned that my thesis might as well be related to Gravitational Waves. Do you think that it would be appropriate to work on Gravitational Waves for a Bachelor's thesis? Isn't it too advanced?
Also, any idea on what part of Gravitational Waves I could discuss?
In my opinion a descriptive thesis that avoids math would be uninteresting. On the other hand, if you could say something about how GR gives rise to propoagating waves, as in https://en.wikipedia.org/wiki/Gravitational_wave#Mathematics
Are you comfortable with that level of math?

pitbull
I'd think it's a suitable topic. I followed GR in the beginning of my third year, and this opens up a lot of interesting topics for a bachelor thesis.

In that direction it could be interesting to dive into linearized GR (= Fierz-Pauli theory), how gravitational waves emerge from such a linearization, and if you want to knot it to some modern research, you could also discuss from that massive gravity theories. Something nice to understand is e.g. why the massless limit of massive Fierz-Pauli theory does not give the results of linearized GR. This is called the vDVZ discontinuity (van Dam-Veltman-Zakharov). See e.g. the excellent notes

https://arxiv.org/abs/1105.3735

Just my 2 cents ;)

pitbull
Depends on whether that professor has published on GW and about how much of the GR courses the uni offers you have followed.

All subjects are advanced at the cutting edge. And GW are no longer conjucture. A BSc thesis is just that. You need something you feel comfortable with as having as your thesis. Something you feel like you can work on for the set time and get some conclusion on before the deadline.

pitbull
Gravitational waves are one of the simplerst solutions of Einstein's equation so that may be a good topic.

However, based on my current interests, I would also suggest thinking about the Reissner Nordstrom black hole. It's a charged black hole which has a lot of very interesting properties. Depending on the values of charge and mass it can have two event horizons, no event horizon, where r=0 is a naked singularity, or an extremal solution which is very mysterious. It has an event horizon (with a very interesting geometry) but is at zero temperature. As you may remember, the area of the event horizon is proportional to the BH entropy. So that means that extremal RN has a finite ground state entropy, which violates the third law of thermodynamics. There is a lot you could do here.

I'm not sure that massive gravity is a good idea since the theory has a lot of pathologies that need to be worked out.

pitbull
jedishrfu said:
Since its for a BS then how about how they traverse spacetime and how LIGO has successfully detected them. Other ideas could be how they are formed and their properties.

https://en.wikipedia.org/wiki/Gravitational_wave

As an aside:

Also one common issue is peoples conflation of gravity waves vs gravitational waves. They are separate phenomena. Here's a link for reference on gravity waves so you can see the difference

https://en.wikipedia.org/wiki/Gravity_wave

DrSteve said:
In my opinion a descriptive thesis that avoids math would be uninteresting. On the other hand, if you could say something about how GR gives rise to propoagating waves, as in https://en.wikipedia.org/wiki/Gravitational_wave#Mathematics
Are you comfortable with that level of math?

haushofer said:
I'd think it's a suitable topic. I followed GR in the beginning of my third year, and this opens up a lot of interesting topics for a bachelor thesis.

In that direction it could be interesting to dive into linearized GR (= Fierz-Pauli theory), how gravitational waves emerge from such a linearization, and if you want to knot it to some modern research, you could also discuss from that massive gravity theories. Something nice to understand is e.g. why the massless limit of massive Fierz-Pauli theory does not give the results of linearized GR. This is called the vDVZ discontinuity (van Dam-Veltman-Zakharov). See e.g. the excellent notes

https://arxiv.org/abs/1105.3735

Just my 2 cents ;)

Asteropaeus said:
Depends on whether that professor has published on GW and about how much of the GR courses the uni offers you have followed.

All subjects are advanced at the cutting edge. And GW are no longer conjucture. A BSc thesis is just that. You need something you feel comfortable with as having as your thesis. Something you feel like you can work on for the set time and get some conclusion on before the deadline.

Gravitational waves are one of the simplerst solutions of Einstein's equation so that may be a good topic.

However, based on my current interests, I would also suggest thinking about the Reissner Nordstrom black hole. It's a charged black hole which has a lot of very interesting properties. Depending on the values of charge and mass it can have two event horizons, no event horizon, where r=0 is a naked singularity, or an extremal solution which is very mysterious. It has an event horizon (with a very interesting geometry) but is at zero temperature. As you may remember, the area of the event horizon is proportional to the BH entropy. So that means that extremal RN has a finite ground state entropy, which violates the third law of thermodynamics. There is a lot you could do here.

I'm not sure that massive gravity is a good idea since the theory has a lot of pathologies that need to be worked out.

Thank you for your answers. The thing is that I have not studied General Relativity yet, so I would have to study it on my own and write the thesis afterwards. All of that during only this summertime. Taking that into account, do you still think that I could manage to write on those topics?

pitbull said:
The thing is that I have not studied General Relativity yet

I don't think it's a good idea to pick a thesis topic first, and then learn about it.

pitbull said:
Thank you for your answers. The thing is that I have not studied General Relativity yet, so I would have to study it on my own and write the thesis afterwards. All of that during only this summertime. Taking that into account, do you still think that I could manage to write on those topics?
Ah, ok, that changes things. Like Vanadium says, you first should learn GR properly to be able to say something sensible about the topics mentioned here. Learning GR can take some time, so I'm not sure it's a good idea to cramp learning GR AND writing a bachelor thesis into two months or so.

## 1. What are gravitational waves?

Gravitational waves are ripples in the fabric of space-time, caused by the acceleration of massive objects. They were first predicted by Albert Einstein in his theory of general relativity.

## 2. How are gravitational waves detected?

Gravitational waves are detected using highly sensitive instruments called interferometers. These instruments measure tiny changes in the length of space caused by passing gravitational waves.

## 3. Why is a Bachelor's thesis on gravitational waves considered advanced?

Studying gravitational waves requires a deep understanding of complex topics such as general relativity, astrophysics, and signal processing. It also involves advanced mathematical analyses and data interpretation techniques.

## 4. What are some current developments in the study of gravitational waves?

One major development is the recent detection of gravitational waves by the Laser Interferometer Gravitational-Wave Observatory (LIGO) in 2015. This has opened up a new field of research and has led to advancements in our understanding of black holes and the early universe.

## 5. How can the study of gravitational waves benefit society?

The study of gravitational waves can lead to a better understanding of the universe and its origins. It can also have practical applications, such as improving our technology for detecting and measuring gravitational waves, and potentially leading to new technologies for space exploration.