Astronomy

I thought only Jupiter had Trojans. Apparently even the Earth has some in its orbit. However, as I think about it, all those planets should have some if Jupiter has them.

Since Moffat's gravity theory made a prediction about gravity waves from the big bang which is different from what the Newton-Einstein theory would predict, I was looking at LIGO which showed the existence of gravitational waves last year. I am not sure what Moffat's prediction is, but at https://losc.ligo.org/about/ there is a tutorial about LIGO's recent findings with an interactive Jupyter notebook allowing you to play around with the data.

It occurred to me that all of these space missions should have something like this and perhaps they do. I just don't know about them.

Sorry, I didn't understand your point bout LIGO. I wondered why you had abandoned the Cosmology thread. Its still there, by the way, just no-one posted on it for quite some time.

There is an interesting post on cubesats: http://www.universetoday.com/82590/cubesat/.

I'm glad to see that CubeSats are being developed. It opens up the exploration of space.

One CubeSat I would like to see is something designed to monitor changes of gravity as the CubeSat went further into space. The Pioneer 10 and 11 missions showed a potential slowing down of the space crafts due to stronger gravity but measurements were not accurate enough to determine whether that was the case or not.

I'll start posting what I find out from Moffat's book in the cosmology thread to help revive it. That might also be a good place for a LIGO/LISA discussion which are instruments that could falsify or validate Moffat's modified gravity theory.

Plans are being made for the establishment of a permanent colony on Mars. Read about it here: http://www.universetoday.com/46816/man-on-mars/

So far, these plans remain very vague and, presumably are likely to be postponed, perhaps even time and time again. This involves NASA but also private interests, and possibly the European Space Agency.

You can read about the history of this idea at the above link.

Solving problems leads to new technologies. So none of this dreaming about Mars is useless. However, we need to test all of it on the Moon first.

Some of the media interest around Mars has only one purpose--to get people willing to spend tax dollars on further space research. I don't think there is any real interest in going to Mars any time this century. If we have a market crash the resulting bearish social mood would make all of this irrelevant since we would not be able to afford it. However, even if we have a crash, I hope we would still be able to afford the LISA gravitational wave observatory.

While tracing links about gravitation, I found this video showing a feather and a bowling ball drop in a vacuum:

https://www.youtube.com/watch?v=E43-CfukEgs

http://www.universetoday.com/46816/astronaut-on-mars/

I had no idea that the Soviets had though so far ahead. Here are discussed many different stages of development from initial dependence on Earth to ultimate full independence on Mars.

I meant to add a comment on the preceding post. Very interesting on the effect of gravity on different objects, YesNo.

On second thoughts, I'm not sure what this post is saying. I thought that with no gravity nothing "falls", only if someone pushes it with their hand or something.

There's gravity, but since it is in a vacuum there is no air resistance on the feathers to stop them from falling as fast as the heavier ball.

But the idea of "falling" is puzzling me at the moment. If the acceleration depends on mass shouldn't there be some difference between the ball and the feathers although tiny?

Also the idea of light bending when going past a massive object (gravitational lensing) does seem like it could be interpreted as mass giving the surrounding space a higher refractive index. Light also bends when passing through water. This refracting approach to gravitational lensing I got from Maya Benowitz in a comment made to a question about the existence of gravitons: https://www.quora.com/Quantum-Gravit...n-detected-yet

From the top of my head I think it is the water's surface that refracts the light. It travels straight through the water. So I don't know if that model holds up.

I listened to a radio programme today from about 10 years ago on the Graviton, (by podcast) So much has moved on since then. The strange idea of the force of Gravity leaking into other dimensions (explaining why it is so weak ) was mentioned.


Just read your link - I agree that Force carrying particles are a difficult concept and would be even more improbable but for the example of the photon which is so active it can be measured. I don't get where the particle ends (eg the Higgs or the Graviton) and the 'field' begins. I suspect the model in my head is not imaginative enough.

OK, this post is from the journal Popular Astronomy (Sept/Oct 2016). NASA's Messenger Mission is not new, it has been circling Mercury since 2008, and collecting data. The most striking discovery is that Mercury's crust is predominantly made of graphite. A second probe, BepiColombo, is due to be launched in 2018, jointly by NASA and the Japanese Space Agency which will fill out the gaps that Messenger was unable to cover due to its orbit. See http://www.open.edu/openlearn/discovermercury.

I must confess I didn't know anything about the Messenger mission until reading this Popular Astronomy article.

Quote:

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Originally Posted by Dreamwoven

Plans are being made for the establishment of a permanent colony on Mars. Read about it here: http://www.universetoday.com/46816/man-on-mars/

So far, these plans remain very vague and, presumably are likely to be postponed, perhaps even time and time again. This involves NASA but also private interests, and possibly the European Space Agency.

You can read about the history of this idea at the above link.

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I don´t doubt that the aim of all this space interest is to create interplanetary human colonies. All this research and space expeditions are very expensive.
I wonder not only when they will be able to start this colonization but what kind of people they will send to space and what will be the survival conditions.

Quote:

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Originally Posted by prendrelemick

From the top of my head I think it is the water's surface that refracts the light. It travels straight through the water. So I don't know if that model holds up.

I listened to a radio programme today from about 10 years ago on the Graviton, (by podcast) So much has moved on since then. The strange idea of the force of Gravity leaking into other dimensions (explaining why it is so weak ) was mentioned.


Just read your link - I agree that Force carrying particles are a difficult concept and would be even more improbable but for the example of the photon which is so active it can be measured. I don't get where the particle ends (eg the Higgs or the Graviton) and the 'field' begins. I suspect the model in my head is not imaginative enough.

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The model in my head is all messed up with bits and pieces from the media. Today, I suspect there is no graviton although a few weeks ago I would have wondered if the graviton had mass just assuming it existed in the first place.

Get your passports ready!

https://www.youtube.com/watch?v=6eirHoHsaQo
Obs. The last question is the one that matters.

Boeing would be a company with resources to do some space research without relying on the taxpayer and governments. Also the ability to send out cubesats reduces the cost of research.

However, I don't see the point of sending human beings on these missions since machines can gather the data better than we can without needing biological and psychological support systems. We should soon have cars and planes that drive themselves. That might be the first step and something that can be done right on Earth: can we get acceptance of self-driving vehicles before the next recession which could slow down such technological change.