Could a Black Hole Cause a Sunrise in the West?

[Ashraf Siddiqui]

Dear All Concerns

Black Hole is formed at the end of life of a big star. The mass of such star should be equal to 5-10 solar masses. But I am imaging very small moving black hole coming to our solar system and passing between our Earth planet and the sun thereby creating solar eclipse of unique type. In this case the sun may rise in the west once a time and then set again in the west. Is there any possibility of such phenomenon in future?

 

[russ_watters]

Black Hole is formed at the end of life of a big star. The mass of such star should be equal to 5-10 solar masses. But I am imaging very small moving black hole coming to our solar system and passing between our Earth planet and the sun thereby creating solar eclipse of unique type.

Unless such a black hole passed very close to Earth it would be too small to see much of anything; It would have a diameter of only 30 km. There are calculators for this online.

In this case the sun may rise in the west once a time and then set again in the west.

Why would you think that? It doesn't sound right.

Is there any possibility of such phenomenon in future?

Not the way you describe it, no.

 

[Ashraf Siddiqui]

The speed of moving black hole should be very high as compared to rotational speed of our earth. The black hole would bend the eastern rays of the sun to (derived) western rays of the sun thereby creating an illusion of sunrise in the west.

 

[russ_watters]

The speed of moving black hole should be very high as compared to rotational speed of our earth. The black hole would bend the eastern rays of the sun to (derived) western rays of the sun thereby creating an illusion of sunrise in the west.

No, it wouldn't work that way. What you are describing really doesn't make any sense. It wouldn't look much different from what happens when Mercury passes in front of the sun. It certainly wouldn't appear to move the sun to a different part of the sky.

 

[snorkack]

No, it wouldn't work that way. What you are describing really doesn't make any sense. It wouldn't look much different from what happens when Mercury passes in front of the sun. It certainly wouldn't appear to move the sun to a different part of the sky.

Certainly would not move disc of Sun.

Mercury does not deflect light that passes its surface. A black hole does.
However, the angle differs wildly depending on the distance from black hole to the ray being deflected.

 

[Ashraf Siddiqui]

It means different phenomenons would be observed on different places of Earth at the same time e.g. : solar eclipse (night), sunrise in the west, sunset in the east etc. due to constant motion of black hole : If it does happened.

 

[Ashraf Siddiqui]

It means if it does happened then different phenomenons would be observed at different places on Earth at the same time.
Solar eclipse (night), sunrise in the west, sunset in the east etc. due to constant motion of black hole. Am I right in guessing?

 

[davenn]

It means if it does happened then different phenomenons would be observed at different places on Earth at the same time.
Solar eclipse (night), sunrise in the west, sunset in the east etc. due to constant motion of black hole. Am I right in guessing?

your guesses are incorrect
you were told that in posts #4 and #6

if you are really interested in astronomy, then you need to start reading up on known science

[edit: OT content deleted by mod]

 

[russ_watters]

Mercury does not deflect light that passes its surface. A black hole does.

Yes, but the sun is pretty much just a bright white featureless blob. A gravitational lens of this would just be a bright ring. So if you superimpose a bright ring over a bright featureless blob it isn't going to look much different. Just a slightly brighter ring but still white and featureless...except as it crosses the edges.

The direct gravitational effects, however, would be potentially cataclysmic.

 

[russ_watters]

It means if it does happened then different phenomenons would be observed at different places on Earth at the same time.
Solar eclipse (night), sunrise in the west, sunset in the east etc. due to constant motion of black hole. Am I right in guessing?

No, gravitational lensing is nowhere near strong enough for that.

 

[Ashraf Siddiqui]

Please forget what I believe. I simply want to know probability of sunrise in the west. May be some other thing would cause this astronomical phenomenon - An optical illusion would be created by ?

 

[russ_watters]

Please forget what I believe. I simply want to know probability of sunrise in the west. May be some other thing would cause this astronomical phenomenon - An optical illusion would be created by ?

No phenomenon can cause that.

 

[snorkack]

Yes, but the sun is pretty much just a bright white featureless blob. A gravitational lens of this would just be a bright ring. So if you superimpose a bright ring over a bright featureless blob it isn't going to look much different. Just a slightly brighter ring but still white and featureless...except as it crosses the edges.

"Bright ring" only on central view.
If a black hole is off-center, most of the Sun´s disc is very slightly deflected. Only the rays that pass very close to the hole are deflected by large angles.

Please forget what I believe. I simply want to know probability of sunrise in the west. May be some other thing would cause this astronomical phenomenon - An optical illusion would be created by ?

Earth atmosphere?
In normal weather, Sun on horizon is refracted 35 minutes upwards. So that Sun which has just set in West is geometrically 35 minutes under horizon.
Suppose that some weather phenomenon should cause the refraction to suddenly increase from 35 minutes to 65 minutes. Then Sun would be seen to rise in the west. Of course, Sun would continue setting and the weather phenomenon might also pass, so Sun would set again.

But do such weather phenomena exist, which might cause the refraction to change so much and so fast?

 

[rootone]

The only event which could cause the Sun to rise in the west would be if the Earth's axis of rotation suddenly flipped to be 180 degrees opposite, (or close to that).
There isn't any way this can happen other than the Earth colliding with another body of at least similar size to Earth.
If that happened it would indeed be the end of Earth as we know it.

 

[russ_watters]

"Bright ring" only on central view.
If a black hole is off-center, most of the Sun´s disc is very slightly deflected. Only the rays that pass very close to the hole are deflected by large angles.

The black hole would need to be very close to Earth for it to cover or lens a large fraction of the solar disk. At the Moon's distance it would only cover 1/10 the diameter of the sun's disk(3 arcmin)...while tearing the Earth apart.

...but I need to put some time into the calculation for the radius of the ring.

 

[unusually_wrong]

No phenomenon can cause that.

What about in the greatly distant future, when the moon has left Earth's orbit: Wouldn't our axis no longer be bound to one teetering location and make it possible that the Earth spins wildly eventually causing the sun to rise in various locations? That is the only time I could think of that it might be possible, but we certainly wouldn't be around to witness it.

 

[rootone]

What about in the greatly distant future, when the moon has left Earth's orbit:

I think it's accepted as being likely that the Moon assists in making the axis of rotation for Earth quite stable.
However, lack of the Moon should not induce very rapid chaotic changes of the axis.

 

[davenn]

Wouldn't our axis no longer be bound to one teetering location and make it possible that the Earth spins wildly eventually causing the sun to rise in various locations?

Why ? yeah, if the Moon suddenly left Earth orbit for some inexplicable reason, it may well reign havoc on Earth
But that isn't happening, the Moon is just very slowly drifting away, a cm or so a year. So there isn't likely to be
any cataclysmic change in the way the Earth spins on its axis etc

 

[russ_watters]

What about in the greatly distant future, when the moon has left Earth's orbit: Wouldn't our axis no longer be bound to one teetering location and make it possible that the Earth spins wildly eventually causing the sun to rise in various locations?

Like anything else that moves, a spinning object cannot change its state of motion unless a force is applied.

 

[russ_watters]

I think it's accepted as being likely that the Moon assists in making the axis of rotation for Earth quite stable.

I'm curious in what way. Per the above, a spinning object is totally stable if left alone. The moon's influence causes precession; what instabilities would it be combatting?

 

[unusually_wrong]

Like anything else that moves, a spinning object cannot change its state of motion unless a force is applied.

It was my understanding that the axis already teeters and that the moon helps keep it from going out of control. Also that the zenith will eventually change from polaris to another star (name is escaping me). So wouldn't the Earth's axis eventually go out of control without the moon to help regulate?

 

[russ_watters]

It was my understanding that the axis already teeters and that the moon helps keep it from going out of control. Also that the zenith will eventually change from polaris to another star (name is escaping me). So wouldn't the Earth's axis eventually go out of control without the moon to help regulate?

If "teeters" means precession, the moon causes that, it doesn't mitigate it. If it is something else, it would still need a cause.

 

[unusually_wrong]

If "teeters" means precession, the moon causes that, it doesn't mitigate it. If it is something else, it would still need a cause.

Here is kind of what I'm trying to explain. It's under the seasons part.

https://www.livescience.com/55477-what-if-the-moon-disappeared.html

 

[rootone]

I'm curious in what way.

I found a number of non crazy sites where this is discussed, and the answer seems to be to with tidal interaction/ torque.
Here's an example (Paragraph 4)
https://www.psi.edu/epo/faq/earth_moon.html

 

[PeterO]

Please forget what I believe. I simply want to know probability of sunrise in the west. May be some other thing would cause this astronomical phenomenon - An optical illusion would be created by ?

The magnetic poles of the Earth have apparently flipped in the past, and will possibly flip again in the future. If everyone continued to believe their magnetic compasses for direction, Europe would then be in the Southern hemisphere, Australia would be in the Northern hemisphere and the sun would rise in the West and set in the East.

 

[russ_watters]

Here is kind of what I'm trying to explain. It's under the seasons part.
https://www.livescience.com/55477-what-if-the-moon-disappeared.html

From the link:

rapidly...
a few hundred thousand years later...
crazy wild swings...
millions of years...
a billion-year problem...

Um, what? Bait-and-switch much? If your head isn't spinning, it gets even worse:

might...
Or not. The moon may actually be hurting us in the long term...

So this "might" happen in a few hundred thousand years -- or a billion -- or never. What this sounds like to me is that scientists have speculated this may be a "thing", but have never actually even modeled it. So it might be a thing or it might not, but certainly not for hundreds of thousands of years or few orders of magnitude longer.

 

[Ken G]

If "teeters" means precession, the moon causes that, it doesn't mitigate it. If it is something else, it would still need a cause.

The cause is the other bodies in the solar system, which have weak effects but start to matter when there are resonances. Both the Moon and the Sun provide the torques that produce the 26,000 year precession, and the precession interacts with the eccentricity of the Earth's orbit to produce climate effects. The potential for various Milankovitch-type cycles makes this a complicated question, but it is certainly quite possible that the presence of the Moon alters the nature of these cycles, and may affect habitability. An influential paper here is Laskar et al. 1993 (https://www.nature.com/articles/361615a0), which asserts that faster precession (assisted by the Moon) helps shorten the time that influences from other planets could destabilize the Earth's axial direction. However, the situation is quite complicated (see https://davidwaltham.com/wp-content/uploads/2013/03/EPSC2013-37.pdf), and the entire area of Milankovitch cycles produces a lot of debate about ice ages and other habitability issues. The fact is, at present we don't really understand exactly why the Earth is so habitable, or how other planets might not be, but there is plenty of potential for anthropic-type selection of the special conditions on Earth, particularly its massive moon.

 

[davenn]

The magnetic poles of the Earth have apparently flipped in the past, and will possibly flip again in the future. If everyone continued to believe their magnetic compasses for direction, Europe would then be in the Southern hemisphere, Australia would be in the Northern hemisphere and the sun would rise in the West and set in the East.

The magnetic poles of the Earth have apparently flipped in the past, and will possibly flip again in the future

not apparently has … they have flipped many dozens of times and there is no reason to suspect they won't in the future

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

this is incorrect

the magnetic poles flip, NOT the geographic poles so my home of Australia, will still be in the southern hemisphere and on top of that ... the Earth will still continue to rotate in the same direction

The northern and southern hemispheres/poles are defined by our geography "labels", not the magnetic polarity.
If it was by magnetic polarity,. The "North" magnetic pole is in the southern hemisphere just off Antarctica.
The "South" magnetic pole is in the north of Canada region ( approx)

The "North" pole of the compass needle points (is attracted to) the South magnetic pole.

and from Wiki ...

Earth's magnetic field, also known as the geomagnetic field, is the magnetic field that extends from the Earth's interior out into space, where it meets the solar wind, a stream of charged particles emanating from the Sun. Its magnitude at the Earth's surface ranges from 25 to 65 microteslas. Approximately, it is the field of a magnetic dipole currently tilted at an angle of about 11 degrees with respect to Earth's rotational axis, as if there were a bar magnet placed at that angle at the centre of the Earth. The North geomagnetic pole, located near Greenland in the northern hemisphere, is actually the south pole of the Earth's magnetic field, and the South geomagnetic pole is the north pole. The magnetic field is generated by electric currents due to the motion of convection currents of molten iron in the Earth's outer core driven by heat escaping from the core, a natural process called a geodynamo.

my boldDave

 

[rootone]

I think we can agree that the unpredictability of Earth's magnetic poles is weird though,
Is there any mainstream theory which it explains it?

 

[davenn]

Is there any mainstream theory which it explains it?

not that I have so far read

 

[russ_watters]

Maybe not specifically, but the general idea is that the liquid core is not spinning consistently with the rotation of the Earth, but rather has some additional bulk movement. Exactly why and how is not really known, but given the planet is geologically active, I don't see this to be a shocking phenomena.
https://www.nasa.gov/topics/earth/features/2012-poleReversal.html

 

[unusually_wrong]

I think we can agree that the unpredictability of Earth's magnetic poles is weird though,
Is there any mainstream theory which it explains it?

From my astronomy 101 class I learned that much like the sun, the magnetic lines get tangled and break causing the pole swap and that we experience it at a far slower rate than the sun.

 

[TeethWhitener]

I simply want to know probability of sunrise in the west

Get in a rocket ship and fly west at greater than the Earth's rotation rate. Eventually you'll catch up with the sun.

Edit: alternately, wait till sunset and go up a tall elevator. The sun will rise again over the western horizon.

 

[JMz]

Earth atmosphere?
In normal weather, Sun on horizon is refracted 35 minutes upwards. So that Sun which has just set in West is geometrically 35 minutes under horizon.
Suppose that some weather phenomenon should cause the refraction to suddenly increase from 35 minutes to 65 minutes. Then Sun would be seen to rise in the west. Of course, Sun would continue setting and the weather phenomenon might also pass, so Sun would set again.

But do such weather phenomena exist, which might cause the refraction to change so much and so fast?

To return to this point: (1) This is 35 arcminutes, or about 4 (temporal) minutes of Earth rotation. (2) Doubling this effect would require increasing the atmospheric density by ~40% [I think, or maybe ~ 100%?] in those 4 minutes of time.

If you see such an effect, it can't be caused by weather. Extreme storms cause atmospheric density to change by ~ 10% over a few hours. So it's presumably caused by a dinosaur-extinction meteoric event.

The corresponding overpressure will travel at somewhat more than the speed of sound (~1000 km/hr), which is just about the Earth's linear rotation speed at mid-latitudes. So it will reach you in less than 4 minutes, and you will die before the second sunset finishes. I hope it's a beautiful one, at least.

 

[stefan r]

Please forget what I believe. I simply want to know probability of sunrise in the west. May be some other thing would cause this astronomical phenomenon - An optical illusion would be created by ?

Huge mirrors could do it. Maybe 2 mirrors with 1.7 km radius with one orbiting at 380km. You would need to go slightly larger to compensate for any angles. Something much less bright than the Sun could resemble the Sun setting. Also a bent mirror could focus light so something smaller than the Sun's angular diameter could appear just as bright. If you want the pink/purple across the horizon effect you could use an array of small mirrors. Not sure why we would do that. Could also put a mirror on a balloon, tall building, helicopter or mountain and reflect the sunset. There is no need for the mirrors to be in the west.

The town of Rjuken in Norway and Viganella in Italy have a artificial suns in the winter. Should work at sunrise for some part of the year. They are set up to bring in a noon sun.

You can buy lights that make artificial sunrises for an alarm. It is supposed to help you wake up. Here is a mechanical artificial sunrise. You could set that in the north and south side of your room too.

Mar's moon Phobos rises in the west, so does the international space station.

In operation Hardtack Teak the USA detonated a nuclear missile in the atmosphere. At some places on the horizon it would have somewhat resembled a sunrise.

There is also atmospheric effects that cause light to distort or flicker. Stars twinkle. Here is a video of a green flash. I would not say that the sun "rises again" but the edge can go over the horizon and briefly reappear.