Page 15 of 17

Science and Astronomy Videos

Posted: 07 Sep 2017 08:06
by DoctorOfSpace

Science and Astronomy Videos

Posted: 08 Sep 2017 17:21
by Spacer

Science and Astronomy Videos

Posted: 09 Sep 2017 07:55
by Mosfet
A Swiss pilot filmed the reentry of the Soyuz capsule from a flight to Singapore:
https://www.srf.ch/news/panorama/swiss- ... ce=srf_app

Science and Astronomy Videos

Posted: 09 Sep 2017 11:21
by Marko S.
This is science video.... I guess.

Science and Astronomy Videos

Posted: 10 Sep 2017 09:35
by midtskogen
Yamal craters explained.

Science and Astronomy Videos

Posted: 13 Sep 2017 02:11
by Watsisname
Why to not take magnetic objects into an MRI:


Science and Astronomy Videos

Posted: 13 Sep 2017 09:32
by midtskogen
Wow.  Magnetic tidal forces. :)

Science and Astronomy Videos

Posted: 13 Sep 2017 12:06
by Mr. Abner
midtskogen wrote:
Wow.  Magnetic tidal forces. :)

Wow indeed. Reminds of that Star Gate SG1 episode where they locked onto a black hole.

Science and Astronomy Videos

Posted: 13 Sep 2017 17:58
by A-L-E-X
Mr. Abner wrote:
midtskogen wrote:
Wow.  Magnetic tidal forces. :)

Wow indeed. Reminds of that Star Gate SG1 episode where they locked onto a black hole.

Ah, I miss that show :(

Science and Astronomy Videos

Posted: 14 Sep 2017 03:26
by Salvo
He didn't create the orbital 3D path, but synchronized photos with time and emotional music makes it an awesome video. I almost had tears.


Do you think we'll have some data from the interior of the atmosphere, or the probe wouldn't have enough time to send it to earth?

Science and Astronomy Videos

Posted: 14 Sep 2017 11:34
by Mr. Abner
Salvo wrote:
He didn't create the orbital 3D path, but synchronized photos with time and emotional music makes it an awesome video. I almost had tears.


Do you think we'll have some data from the interior of the atmosphere, or the probe wouldn't have enough time to send it to earth?

I'm no rocket scientist, but I'd wager that she will burn up well before hitting any visible cloud layers.

Science and Astronomy Videos

Posted: 14 Sep 2017 19:49
by Watsisname
Yeah, Cassini will be turned into vapor far above the cloud tops.  Its entry speed will be over 30km/s (4 times as fast as return from Low Earth orbit and 3 times as fast as return from the Moon), and it has no shielding.  To survive very far into a gas giant's atmosphere would require some serious shielding like the Galileo probe that went into Jupiter.

Added:  Very nice explanation of some of the weirdness of quantum mechanics that can be observed with simple equipment.  (Collaboration of minutephysics and 3Blue1Brown).


Science and Astronomy Videos

Posted: 15 Sep 2017 02:06
by A-L-E-X
Thanks, Wat, I also like some of the ways that quantum mechanics extends to the macro level (for example photosynthesis and other aspects of quantum biology including heredity.)  I don't find it weird at all, I just find our senses limiting in how much they can perceive.  For example, there is no such thing as "solid" matter, or "particles" (in the sense that we envision them) and "locality" for that matter.  On that level, space and time cease to exist.  We relate more closely to that which we sense around us, but quantum mechanics is the math that underlies it all at the most basic of levels.

PS I also like the experiments of the Casimir Effect that we used to do.  It shows how dynamic even so-called empty space can be!

Science and Astronomy Videos

Posted: 15 Sep 2017 05:21
by Watsisname
As the video caption says, it is weirder than you think. :) 

Quantum mechanical effects being apparent to our senses is cool but not in itself weird or even rare.  The colors of fireworks and neon signs are determined by the quantum mechanical behavior of electron transitions.  One of my favorite examples is that the double yellow line of Sodium is due to the effects of electron spin.  The function of a digital camera is also quantum mechanical.

But the weirdness in this case involves a much more fundamental question:  "how does the universe decide the outcome of an experiment?"  The most tempting, obvious answer is that the process involves properties we cannot measure.  That there are limits to what our senses and instruments can detect.  Those would be hidden variables.  But what the Bell inequalities are showing is that this explanation does not work, without discarding something which relativity also tells us is very fundamental to the universe -- locality. 

I don't think abandoning space and time on that level helps us.  A wave function itself contains both spatial and temporal parts.  The Schrodinger equation literally says "the second rate of change of the wave function with respect to space, and the first rate of change with respect to time (with some additional bits for the energy & momenta operators), are equal.  So any philosophical explanation for the behavior of quantum mechanics requires deeper thinking.  In over 50 years of thinking people have come up with several, but they don't appear distinguishable by experiment -- they're interpretations rather than models.

The notion of space itself being dynamic is one of my favorite things.  General relativity and Cassimir effect are classic examples, but even plain old electric and magnetic fields can be described as a property of "empty" space.  They also make a good illustration of how what we feel as solid objects are just those fields on a very small but strong scale.

Science and Astronomy Videos

Posted: 15 Sep 2017 13:45
by A-L-E-X
Watsisname wrote:
As the video caption says, it is weirder than you think. :) 

Quantum mechanical effects being apparent to our senses is cool but not in itself weird or even rare.  The colors of fireworks and neon signs are determined by the quantum mechanical behavior of electron transitions.  One of my favorite examples is that the double yellow line of Sodium is due to the effects of electron spin.  The function of a digital camera is also quantum mechanical.

But the weirdness in this case involves a much more fundamental question:  "how does the universe decide the outcome of an experiment?"  The most tempting, obvious answer is that the process involves properties we cannot measure.  That there are limits to what our senses and instruments can detect.  Those would be hidden variables.  But what the Bell inequalities are showing is that this explanation does not work, without discarding something which relativity also tells us is very fundamental to the universe -- locality. 

I don't think abandoning space and time on that level helps us.  A wave function itself contains both spatial and temporal parts.  The Schrodinger equation literally says "the second rate of change of the wave function with respect to space, and the first rate of change with respect to time (with some additional bits for the energy & momenta operators), are equal.  So any philosophical explanation for the behavior of quantum mechanics requires deeper thinking.  In over 50 years of thinking people have come up with several, but they don't appear distinguishable by experiment -- they're interpretations rather than models.

The notion of space itself being dynamic is one of my favorite things.  General relativity and Cassimir effect are classic examples, but even plain old electric and magnetic fields can be described as a property of "empty" space.  They also make a good illustration of how what we feel as solid objects are just those fields on a very small but strong scale.

I got to experience some "quantum weirdness" myself when I was researching camera sensor specs for astrophotography and had to teach myself about quantum efficiency, etc.  It's interesting how much we take for granted that works because of it.  Isn't our sense of smell also linked to quantum mechanics?  And the way birds navigate during their migrations?
Wat, do you think locality can both be kept and abandoned?  In other words could it be an emergent property on a macro level but not exist on the basic quantum mechanical level? I posted an article which stated that locality has to go for a viable quantum gravity theory to emerge.  I guess you could say the same thing about space-time being emergent, or at the very least not working the same way at the basic level.  According to Loop Quantum Cosmology it consists of discrete units rather than being continuous (which removes singularities from the math.)  So far, no proof of these discrete quantized units of space-time though.

I like the different interpretations of quantum mechanics (even quantum mind theories a la Penrose) but I haven't seen one that seems "more right" than the others (enough to overturn Copenhagen at any rate)- including my favorite, MWI and David Deutsch's variation on it and various transactional interpretations- perhaps something vital is missing.  I also agree with you about our problems with observations at that level- the Heisenberg Uncertainty Principle becomes a huge factor- although I have read some stuff that there may (partially) be a way around that by lowering the margin of error by a significant amount.

In some ways, I like to think of black holes as quantum mechanical objects on the macro level.