Janus

Finnish: kuusi palaa

could translate to any of the following:

The spruce is burning
The spruce returns
The number six is burning
The number six returns
Six of them are burning
Six of them return
Your moon is burning
Your moon returns
Six pieces

I remember seeing it back when it was originally aired.

11 hours ago, Hello2 said:

I’m having questions with this:

 

Is it so that the further the galaxie, the larger the redshift?       

 

And: Are there galaxies with a constant redshift, or is it so that all galaxies with a redshift have a redshift that is increasing?

 

Further objects only have a larger red-shift due to the fact that the universe is expanding.  If the universe did not expand, there would not be any change in red-shift with distance.

The amount that the red-shift of any particular galaxy will have changed over the period we have been measuring them is too small to notice.

But that doesn't mean that we can't measure how fast the universe was expanding in the past.  When we look at the light from a galaxy, that light tells us the state of that galaxy when the light we see now left it.  The further the galaxy is away from us, the longer it takes the light to reach us.  Thus, as we look at galaxies further and further away, we are seeing them as they were when the universe was younger and younger than it is now.  That includes how fast they were receding from us, and the red-shift that the recession produces.

If the rate of expansion had been constant over time, you would see a one to one relationship between distance and red-shift measurements of recession speed.  If you measure anything else, that means that the rate of expansion has changed over time. It is that simple.

18 hours ago, Jalopy said:

I discovered on google that the speed of light and the speed of gravity are the same.

Does that mean that gravity fails to have any effect on light, because gravity and light travel at the same speed?

i.e is that why light has no mass?

 

What are the same are the speed of light (in a vacuum) and the speed of gravity waves.  Gravity waves are not gravity itself, but more like ripples traveling through the gravitational field. Put another way, you can't have gravitational waves without there already being a gravitational field, but you can have a gravitational field without gravitational waves.

Light interacts with the gravitational field, which is "already there"

As already mentioned, light has no "rest mass".  However, it still can interact gravitationally.  While in Newtonian physics you need mass to do so, under our more recent understanding of gravity(General Relativity), mass is just one factor that can contribute to gravity. Energy is another, and light does have energy.

5 hours ago, Jalopy said:

 

 

in outer space, there is no gravity

Where did you get that idea?

4 hours ago, TheVat said:

I have two grandparents born in Scandinavia, but am not sufficiently fond of cold (live in South Dakota, so it's nothing new to me, either),  20 hour nights, or those countries.   In a civil war here, I would probably just hunker down.  (what's a bit ironic is that one of my relatives was a polar explorer)

So I assume either Norway or Sweden or possibly Denmark? (Finland is not actually a part of Scandinavia). My paternal grandfather was born about 100 miles south of the Arctic circle, and  some ancestors from further North.

2 hours ago, MigL said:

kind of cold in Finland.
You might as well move to Canada.

Ah, but here's the beauty of it: Everyone will be wanting to go to Canada, but only 0.2% of the US population has any claim to Finnish ancestry at all.  Having 4 Finland-born grandparents should put me at the front of the line!

(Besides, I was born and raised in Northern Mn, cold is nothing new to me.)

Today I learned, that if I chose to, I could move to Finland. 

If you want to stay in Finland longer than the 90 days allowed by a visa, you need to apply for a residence permit.  Here are a few reasons you could be granted one:  You've been hired for a job in Finland. You have immediate family( spouse, child under 18.) that already live there. You are going to school there...

But the one that would apply to me is "remigration"; If you have Finnish roots, or a close connection to Finland. So, for example, if a grandparent had been born in Finland.  This is me. All 4 of my grandparents were born in Finland( as were their parents, and so on) 

And while most of the other methods of getting a residence permit requires that you can show that you have sufficient funds/income to support yourself, remigration doesn't.

Not that I have any plans to do so, but it is nice to have it my back pocket in case things really go sour here in the US ( civil war breaks out, e.g.) 

2 hours ago, beecee said:

I read that as similar to asking what is the minimum most  stable orbital distance, something can orbit a BH? Which would be actually the photon sphere at 1.5 Schwarzchild radius.

Where would that be for a Neutron star, (as opposed to Magnetar and Pulsar)

The maximum mass for a neutron is star is ~2.17 solar masses, and one that massive would have a radius of ~15 km.

The event horizon for a BH with that mass is ~6.43 km, and has a photon sphere at ~9.65 km.    At the surface of the Neutron star, escape velocity would be ~ 0.463 c and orbital velocity would be ~0.33 c, both well short of c.

13 hours ago, Marius said:

If its not an actual bending of anything then why do mainstream scientists keep pretending that it is ('matter tells space how to curve, and space tells matter how to move'), and keep giving the same fabric sheet example over and over ?

And how is the aberration in the video an accurate description of reality ? Do you seriously think that it has anything to do with  reality ? Where do you think you are, the Matrix ? 

They say it this way when trying to communicate the idea of non-euclidean spacetime to a general populace that has no idea what non-euclidean geometry is.

The animation is not meant to represent "reality", it is a "translation" of non-euclidean geometry using euclidean geometry.  It is an attempt to represent an abstract concept in a way that is easier to visualize.

17 hours ago, Marius said:

 

Like any wave, the light wave looses some of this energy as it passes vast distances of space (due to interactions with free electrons, plasma, gas clouds, and so on).

 

46 minutes ago, Marius said:

And why would I assume such non-sense that 'space itself expands' ? When I can explain the galactic redshift in static space with a simple formula that relates energy to frequency ?  

 

Well, for one, the mechanism you use to explain this frequency shift ( quoted above) would not result in the type of frequency shift we see.  All these types of interactions are wavelength dependent, meaning that the effect you get from them depends on the wavelength of the light (An example of this type of wavelength dependent effect would be light at the blue end of the spectrum being scattered more by our atmosphere*)   Thus you would see different amounts of shift in spectral lines at different points of the spectrum, and not the uniform shift we see across the whole spectrum.  It's not enough to say you can relate energy to frequency when the mechanism that you attribute this change to would not produce the results we observe.

* In fact, the very mechanism you base your argument on would also produce scattering.  We do not see significant scattering in light from distant galaxies. (because, quite frankly, there isn't enough stuff out there between our galaxy and them to produce it.  The amount of material a photon passes on its way between a galaxy 13 billion ly away and our galaxy is roughly equivalent to the amount it passes crossing 1 meter of air at sea level.)

18 hours ago, swansont said:

Folks, it’s fiction. Things are made up. There are attempts at continuity and they tried to not botch the science too badly, but at the end of it all, they’re telling a story.

A friend from high school spent a year as the TNG science consultant (later was on the writing staff); I complained one time about an episode’s science and he admitted he was overruled because the writers liked the story line. 

There’s an excellent chance the discussion of the efficiency was to advance the story. 

 

 

Exactly, a lot of this background on " how things work" on a starship(BTW, the info I provided came from the  Star Trek The Next Generation Technical Manual by Rick Sternbach and Micheal Okuda ) are loose guidelines to maintain some continuity, but they are not allowed to get in the way of a good story line. 

1 hour ago, AstroK32 said:

That is one thing I was wondering about. How exactly do they generate electricity from the warp core? Also, my apologies for the late response, I was at a funeral.

Most likely by magnetohydrodynamic generator.  Where you pass plasma through a magnetic field to generate electricity.  This seems to fit with other nomenclature in the franchise.  There are references to the EPS (electro plasma system), which seems to be how they tap energy for running ship systems from the PTC (power transfer conduit), which contains and carries plasma from the matter-antimatter reaction chamber to the warp field generator coils.

16 hours ago, Jamey said:

you can say what you want about old data, all I know is that if you take the time to put the continents together yourself and realize the structure forms a complete ball minus the underside, and the alignment of the island itself says it was a moon that fell. I have a BA in mechanical engineering, and common sense will tell you the accuracy of my claim, if you put it together to the ball and line it up on a globe. there is no doubt at that time. 

Moon's don't just "fall" or "lose orbit",  as that is not how orbits work.  As far as arriving at a conclusion via "common sense" goes, in my experience, it very often is actually arriving at a conclusion by starting with insufficient or just plain incorrect information, and then applying faulty logic to it.
 

4 hours ago, joigus said:

This is hands down one of the silliest ideas I've ever heard.

Just to add a couple more to what Studiot already said:

What about nicely-deposited billions-year-old sedimentary rocks, and surfaces of rock with the unmistakable fingerprint of ancient tides and water waves?

What about the perfectly-preserved fossils (billions of y.o.) of stromatolites?

How did they survive the crash?

Do you have any idea of the range of collision velocities for astronomical bodies?

 

And then there is the fact that Pangaea is just the most recent of a series of super-continents  that formed and then broke up.

The second image is an analogy which visualizes space as being 2 dimensional and bent through a third dimension.  It is not representative of reality.  

In it all of space is the surface shown as a grid. And while the diagram shows the Sun and planets as solid objects sitting on that grid, they would better be represented as circles on the surface.  Like already stated in order to make it simpler to present, 2 of the spatial dimensions are removed.

Here's am animation that gives an idea of what this same analogy would look is you included the other two dimensions

  The other thing to keep in mind is that the "Curvature" of space-time is not an actual bending of anything.  It is a term used to convey the idea that space-time deviates from  the rules that govern Euclidean geometry in the presence of mass.  It is called curvature because it gives results like those you would get if you try to do plane geometry on a surface that is not flat.

To build on exchemist's point.

Let's assume your flywheel is a magnet, and you've placed a coil nearby, but not touching it in any way. Essentially making a "frictionless" generator.

Your flywheel will continue to rotate unabated until you attach some type of load( say a light bulb) to the leads of your generator.

When you do this, current begins to flow through the wires including the coil.  This, in turn turns the coil into an electromagnetic, the polarity of which will apply an opposing force to the flywheel, slowing it down.  Keep the light hooked up long enough, and the wheel will stop spinning entirely.  Even there were no losses in the system, the total light energy produced by the bulb could only ever equal the total KE stored by the flywheel (which you would have had to have added to spin it up)

On 11/20/2021 at 12:12 PM, DeckerdSmeckerd said:

From what I was able to determine, even though the solar system's orbital plane is 60 degrees tilted from the galactic plane, the planetary bodies fall toward and rise away from the center of the galaxy. 

I think of a gravity well as a direction down (just for the sake of describing my thought) since that is how we think of it while on earth. Up is away from the gravity and down is towards it. If the center of the galaxy exerts even the slightest of gravity on our solar system then the direction towards it is down. (Just for the sake of describing my thought process). That means everything wants to fall toward it unless there is some force that counteracts it. Even though it might be too weak to move the ocean, I don't see why the planets would not fall toward that distant gravity well because no matter how weak it is, it is still the natural direction for things to fall. I have checked our solar system and they do fall around our Sun in this way.

 

The point is that this "down" is the same for everything in the solar system and they all react equally to it.  While the planets do "fall" towards the center of the galaxy, they do not tend to do so any more than the Sun does. The solar system is so small compared to the distance to the center of the galaxy, that any difference in gravity acting over it caused by the galaxy's mass is insignificant. ( a quick calculation indicates that some nearby stars would have a larger effect.)

Secondly.  Even if there was a measurable differential across the solar system, it would not cause the orbital plane to align with it. The solar system is a rotating structure, and when you apply a force in order to try to change the axial orientation of a rotating structure you get a precession instead. (the axis "wobbles")

Now, since the rate of this precession depends on a number of factors, including the angular velocity of the rotating structure, and each planet orbits the Sun at different angular velocities, each planet's orbit acts as a singular rotating structure with its own independent precession rate.  Thus, over time, you would end up with planets orbiting at all kinds of orientations to each other and not nearly in the same plane as we have now.  The fact that all the major planets, for the most part, share the same orbital plane shows that there has been no significant force acting on it in this way.

16 hours ago, DeckerdSmeckerd said:

For example, if you drew a line along Uranus's rings and equator and did that through one entire revolution of Uranus around the Sun, where is that intersection? (Do I need to explain the orientation of the line in respect to the Sun. I can try to but I don't have the terms.) Maybe it points to something with mass? It is further from the Sun than Saturn is. Saturn's are oriented towards the Sun, I read. (Or perhaps there is something undetected that is closer to Uranus).

If Saturn's rings were oriented toward the Sun, then we would not see them as well as we can from Earth (since we'd always be looking at them nearly edge on.)

Sure, twice an orbit, the ascending or descending nodes of the rings align with the Sun, But since the ring orientation remains nearly fixed relative to the stars as it orbits, this has to happen no matter how they are oriented.

On 11/19/2021 at 5:57 AM, DeckerdSmeckerd said:

if you drew a plus sign on our orbital plane and one line is 60 degrees in respect to the galactic plane, I wonder where the other line in the plus points in respect to the center of the galaxy. I assume he means that the plane is at 60 degrees in the direction we are traveling. I could be wrong about what I think he means but he doesn't say it is at 60 degrees toward the center.

 

Super interesting article. Thanks for that.

edit: I also wouldn't want to disregard the 60 degree angle. I would want to look along that plane all the way in a circle and see if there are any other gravity wells. 

I also would like to draw a line through the perigee and aphelion of the planetary orbits and see if there is anything out there in either direction. Of course, I don't know if these things change over thousands or millions of years as we revolve around the galaxy center, so if they are attracted to gravity wells, they might shift between different wells during the revolution.

The only effect the gravity well of another body would have on the orientation of the orbital plane of our solar system would be through tidal forces( the part of the solar system closest to the body being pulled on more than the part further away)* Tidal forces fall off by the cube of the distance. This means that the mass causing them generally need to be fairly close. For example, even though the Sun is nearly 27 million times more massive than the Moon, the fact that the Moon is 1/400 the distance of the Sun results in it having the larger tidal effect on the Earth.

There are no bodies with the right combination of mass and distance to produce any significant tidal effect on the Solar system.  The galaxy itself is very massive, but its center is so far away that, for all intents and purposes, all parts of the solar system are an equal distance from it.

The perihelion and aphelion of the various planets do shift over time, but that's due to interactions between the planets themselves. They also do not line up with each other.

In addition, while the major planets do tend to orbit in almost the same plane, there are plenty of bodies that do not, asteroids, comets, etc. Comets in particular have large, very elliptical orbits, and because of this, they would be much more prone to be effected by external tidal forces acting on the solar system as a whole.  We do not see any pattern to them that would suggest that they are being effected in such a way. 

To expand of swansot's post:   When you look at the spectrum of a distant light source like a star or galaxy, the spectrum will contain bright and dark lines.  These are the emission and absorption lines from the different elements in the source.  Every element has a distinct pattern of lines that occur at a particular point of the spectrum.

If the light from the source is absorbed/scattered, you will see a dimming of a certain part of the spectrum, but those lines will still be there, in the same pattern and same part of the spectrum because all that is happening is that you are receiving a smaller proportion of light from one end of the spectrum.

With red/blue shift, what we see is all these spectral lines shifted to new positions in the spectrum. So for example, a pattern that normally is in the yellow part of the spectrum will move towards the orange.  You may not even notice much of a change in the overall "redness" or "blueness" in the spectrum as a whole, as non-visible frequencies shift into the visible at the red end, and visible light at the blue end shifts into the non-visible range.

Masks serve a dual purpose:  Protection of the user from others who may be infected, and protection of others from the user if he/she is infected.

And of the two, they are more effective with the later.  Valves in the mask work to defeat this by allowing more water droplets to escape the mask.

People need to to stop thinking of masks in terms of something they wear to "just protect themselves",  and more as something  that we, as a community, should wear to protect each other.

10,000 meters in the track frame.  If the lightning strikes occur 100 m apart in the train frame, then scorch marks they leave on the tracks are 100 m apart as measured from the train frame.  Since the train measures the track as being length contracted by the same factor ( 1/100) as the track frame measures the train, then the proper distance between the scorch marks as measured from the track frame is 100m x 100 = 10,000 m.

Of course this means that the rear of the train ( being only 1 m long as measured from the tracks) reaches the point on the tracks where it and the tracks are hit by lightning while the front of the train is still 9,999 m short of where it will be struck by lightning, making the lightning strikes non-simultaneous in the track frame.

20 hours ago, TheVat said:

Depends on the mass difference and distance between planet and moon.  If the moon's mass is great enough that the barycenter is outside the moon's sphere then,  as with Pluto and Charon,  both bodies will be tidally locked to each other as they both orbit their common center of gravity which lies between them.    The effect will override any tidal locking from the primary,  the M star.   I'm afraid I don't have the math handy on locating the barycenter.   

The question is if,  unlike Pluto and Charon,  a close-in planet could possibly be close enough to a dwarf star to disrupt the mutual lock between the planet and big moon.   Seems unlikely,  but we could use a second opinion.   

While a Moon's tidal influence can dominate, the star will have a tidal influence.  For example. Let's start with a planet-moon system tidally locked to each other, The star will still will still produce tidal effects that will produce drag on the Planet's rotation. If this were allowed to happen, then the Moon would orbit faster than the planet rotates. In this situation, the Moon would spiral in, transferring rotational energy to the planet, speeding up its rotation. 

So what happens is while the Moon does end up keeping the planet tidally locked to itself, it does so at the expense of  it's own orbital energy. Both it's orbital period and the rotational period of the planet shorten.  However, this can't be maintained forever, as eventually the moon would spiral inside the Roche limit and break up. How long this would take depends on the tidal influence of the star.   For example, Proxima Centauri B orbits so close to its star that the stellar tidal forces on it are roughly 1000 times that of the Sun on the Earth.

2 hours ago, Paul Singh Jr said:

But isn’t gravity basically a magnetic field 

Would the same principle apply

Magnetic fields have polarity. You have a North and South pole. Like poles repel each other and unlike poles attract.

The poles always occur in pairs (a magnet will always have both North and South poles)

Because of this, it is possible to arrange the poles in such a way that all the poles cancel each other out and you get no net attraction or repulsion.

Gravitational fields have no polarity.  They are purely attractive; mass attracts mass.  The more mass, the greater the attraction. There is no way to arrange things to get a repulsion or cancellation.

But, compared to magnetic fields, gravity is very weak, and it take a considerable amount of mass for this attraction to be easily measured.

But, as swansont has already noted, we have measured gravitational attraction between relatively small masses.

The earliest such measurement was done by Henry Cavendish in 1797.

He took two brass* spheres which were placed on the ends of a long rod which, in turn, was hung from a piano wire at its midpoint.  Two more larger Brass spheres were placed near the suspended spheres so that any attraction between them would rotate the rod and twist the piano wire. Then, by measuring how much rod rotated, and knowing how much torque it would take to twist the wire by that amount, he could work out just how much force was attracting the spheres to each other.  And since he also knew the mass of the spheres, he was able to derive the constant of proportionality for gravity.

This, in turn allowed him to work out the mass of the Earth.  Up until then, while we could measure how much gravitational force there was between the Earth and an object of a known mass, and we knew how far the object was from the center of the Earth, we were still left with two unknowns: the mass of the Earth, and the gravitational constant of proportionality.  Knowing either one would allow us to work out the other.  

Cavendish's experiment gave us the value of the gravitational constant, which meant he could now calculate the Earth's mass. Because of this, Cavendish has been referred to as "The man who weighed the Earth".

*he used brass as it had no magnetic properties that could have skewed the results.

1 hour ago, cyborgjrf said:

Was the theory used to develop that time is effected by gravity were they based upon the use of an atomic clock? If so the electron has mass and thus it is effected by gravity and would that cause any frequency variations. Thus my questions is the effect of gravity on time an insight to possible travel or displacement  based upon the interaction of mass with gravity using  frequency? just my thinking as I start my learning of Atomic physics. ( I am referencing the claims of South American Shamans claims in the book A separate Reality)

 

When we say that gravity has an effect on time, it is important to understand, that is a difference in gravitational potential that is important and not any difference in local gravity strength.  A clock at the top a mountain runs faster than one at sea level because it is higher in the gravity well of the Earth, not because gravity is a bit weaker there.

If fact, if gravity didn't decrease with altitude, and remained the same at the mountain top as at sea level, not only would the mountain clock still run faster, but the difference between its tick rate and the sea level clock would be even larger. This is despite the fact that both clocks would experience exactly the same magnitude of gravity.