Are these birds, planes or satellites, or meteors?

[lucas_]

Dear experts,

What are these things (dozens of them):



Are these birds, planes or satellites, or meteors? Has anyone seen anything like these?

 

[pinball1970]

Dear experts,

What are these things (dozens of them):



Are these birds, planes or satellites, or meteors? Has anyone seen anything like these?

The link does not work for me, can you post in another format please?

 

[lucas_]

The link does not work for me, can you post in another format please?

Is youtube blocked in UK?

try to copy and paste these... just connect the "you" and "tube" as one word.

https://www.you tube.com/watch?time_continue=7&v=Qo8ReWwoOQE

 

[pinball1970]

Is youtube blocked in UK?

try to copy and paste these... just connect the "you" and "tube" as one word.

https://www.you tube.com/watch?time_continue=7&v=Qo8ReWwoOQE

YT usually ok, what's the title of the vid? I'll open in another window

 

[lucas_]

YT usually ok, what's the title of the vid? I'll open in another window

click the link


or

 

[Klystron]

The motion of the flock appears bird-like. If filmed from an aircraft, the altitude would help decide. From reading books Moscow is surrounded by avian flight paths. Filming migratory birds at night, if true, is quite a coup.

 

[pinball1970]

click the link


or

That's cool.
No idea what it is though, @mfb posts on space type stuff

 

[lucas_]

That's cool.
No idea what it is though, @mfb posts on space type stuff

Klystron said they were flocks of birds. Usually how high can birds fly?

If they were satellites. Can they move that fast?

 

[Klystron]

Klystron said they were flocks of birds. Usually how high can birds fly?

If they were satellites. Can they move that fast?

Correction. I said the motion of the objects appeared bird-like; that if the objects are birds flying between the camera and the moon that their motion seems consistent with a flock of birds.

Without analysis we could be watching almost anything including a composite video. A fun interesting video in any case. Thanks.

 

[lucas_]

Correction. I said the motion of the objects appeared bird-like; that if the objects are birds flying between the camera and the moon that their motion seems consistent with a flock of birds.

Without analysis we could be watching almost anything including a composite video. A fun interesting video in any case. Thanks.

Here is the zoomed out city shot before the camera was zoomed to the moon (jump to 19 seconds):

 

[Klystron]

I watched the longer video. The lead credits are Portuguese? The audio Russian? Have you heard/seen a translation into English?

I mistook the background sounds for aircraft engines but the wider shot puts the camera at ground level in the city; so, likely traffic noise. The circular artifacts that appear around the dark objects are confusing, but otherwise they resemble a flock of large birds. Could be an illusion or more artifacts but does anyone else see flapping wings?

I do not see motion consistent with ballistic behaviour. One would expect a meteor entering the atmosphere to glow against the dark sky at some point while these objects are only backlit by the full moon. One would also expect airplanes flying in such close formation to display safety lights. Also would expect satellites in orbit to reflect sunlight when the aspect is favourable.

Birds or bats are not ruled out. I have seen large bats flying at night in Asia and small bats in North America. These objects seem to be flying higher than bats normally hunt and, the "wing beats", if that is what we see, seem more consistent with birds than bats.

I just noticed this thread is in an Astronomy forum, not general discussion.

 

[berkeman]

That's not how formations of planes and birds fly together. They would be flying in a "V" formation or "Echelon" formation for efficiency.

They look more like satellites to me, and since there have been recent lauches that released a gaggle of small Internet communication satellites all at once, that would be my vote. @mfb has posted a thread or two about those launches. The timing of the video looks about right for one of those launches, but I'm not sure without searching out the launch and satellite release profile info.

 

[berkeman]

Here are a couple of the threads I was thinking of...

https://www.physicsforums.com/threads/satellite-internet-constellations.971771/
https://www.physicsforums.com/threads/starlink-launch-first-60-satellites.972023/#post-6179480

 

[Klystron]

Thanks for this new (to me) information on satellite clusters. Also explains the circular shapes.

 

[mfb]

Certainly not satellites in low Earth orbit. They move at 7 km/s in a distance of 500-1000 km or ~0.5 to 1 degree per second - they cross the disk of the Moon in just 0.5-1 seconds.

Geostationary satellites need ~2 minutes, but they shouldn't have such a density. In addition they are in sunlight nearly the whole time. They only enter the shadow of Earth briefly every orbit in two eclipse seasons close to the equinoxes, end of February to mid April and late August to mid October. If the video is from May 18 then geostationary satellites are bright spots, not dark.

I estimate 1 minute to cross the Moon. For objects nearby this means 2 minutes for 1 degree. If the objects are 600 m away they move with 5 meters per minute. Too slow for anything flying, even if we take into account that we don't see radial motion. 6 km away, 50 meters per minute? Still too slow.

Dead pixels and the zooming is done electronically? Dark spots on the telescope?

Helium balloons released by a school or some other event?

Thanks for this new (to me) information on satellite clusters. Also explains the circular shapes.

This seems to be coming from the resolution of the video. The Starlink satellites have the shape of a long rectangle, by the way (from the solar panels), and they were launched May 24, a week after this video.

 

[lucas_]

Certainly not satellites in low Earth orbit. They move at 7 km/s in a distance of 500-1000 km or ~0.5 to 1 degree per second - they cross the disk of the Moon in just 0.5-1 seconds.

Geostationary satellites need ~2 minutes, but they shouldn't have such a density. In addition they are in sunlight nearly the whole time. They only enter the shadow of Earth briefly every orbit in two eclipse seasons close to the equinoxes, end of February to mid April and late August to mid October. If the video is from May 18 then geostationary satellites are bright spots, not dark.

I estimate 1 minute to cross the Moon. For objects nearby this means 2 minutes for 1 degree. If the objects are 600 m away they move with 5 meters per minute. Too slow for anything flying, even if we take into account that we don't see radial motion. 6 km away, 50 meters per minute? Still too slow.

Dead pixels and the zooming is done electronically? Dark spots on the telescope?

Helium balloons released by a school or some other event?
This seems to be coming from the resolution of the video. The Starlink satellites have the shape of a long rectangle, by the way (from the solar panels), and they were launched May 24, a week after this video.

If Earth referenced objects were traveling at 100 knots. How long would it take to cross the disk of the moon?

The USS Nimitz Carrier Strike Group with the most sophisticated Aegis radar that can simultaneously track 100 objects were able to detect similar fleet of objects that descends from the higher atmosphere at daytime and maintain position at 100 knots. Jump to about 4:00 minutes in this video to see the photos and radars:

https://www.bing.com/videos/search?...8C8316050BF604138DB38C8316050BF6041&FORM=VIRE

 

[mfb]

If Earth referenced objects were traveling at 100 knots. How long would it take to cross the disk of the moon?

That depends on their distance, see the example numbers I gave. The Moon has half a degree in the sky, or ~1/100 as diameter/distance ratio. Find the time the objects need to travel 1/100 their distance to the camera.

 

[lucas_]

That depends on their distance, see the example numbers I gave. The Moon has half a degree in the sky, or ~1/100 as diameter/distance ratio. Find the time the objects need to travel 1/100 their distance to the camera.

Let's assume these were the size of jetfighters (or propeller based airplane) and the speed is 100 knots (I read "For jet airliners the stall speeds may range from around 100 knots when light (~185 km/h, ~115 mph) to maybe 130 knots (~240 km/h, ~150 mph) when loaded", what is the stall speed of typical jet fighters)?

So assuming they were the size of jet fighters. If the speed is 100 knots. How far should it be from ground in the case the moon is 30 degrees above the horizon (in the city backgrounded video)?

 

[mfb]

Just... calculate it?
100 knots * 100 minutes = 300 km away
30 degrees above the horizon would mean half of that above the ground, or 150 km. That is in space. Give or take a factor 2 depending on the flight direction.

You could find a flight profile where the jets are rising or descending by just the right amount to have a nearly radial motion, but that isn't very realistic.

 

[lucas_]

Just... calculate it?
100 knots * 100 minutes = 300 km away
30 degrees above the horizon would mean half of that above the ground, or 150 km. That is in space. Give or take a factor 2 depending on the flight direction.

You could find a flight profile where the jets are rising or descending by just the right amount to have a nearly radial motion, but that isn't very realistic.

Let's say these objects were the Russian space force and 150 km above or in space and traveling at 100 knots. Would it move with the speed just like the unknown dark objects in the video?

Or for the objects to be 150km or in space, what speed should it be so it can match the speed of the objects as they cross the disk of the moon in the video?

 

[russ_watters]

Klystron said they were flocks of birds. Usually how high can birds fly?

If they were satellites. Can they move that fast?

Was this filmed from the ground? As almost points, the altitude can't be determined.

And regardless of altitude these objects were flying incredibly slowly, not fast. That's why I'd consider a cluster of balloons in almost still air possible.

 

[russ_watters]

Let's say these objects were the Russian space force and 150 km above or in space and traveling at 100 knots. Would it move with the speed just like the unknown dark objects in the video?

Or for the objects to be 150km or in space, what speed should it be so it can match the speed of the objects as they cross the disk of the moon in the video?

No. None of that makes any sense. Don't do that. We're indulging a little fun in your Death Star thread, but this is a science forum.

Or for the objects to be 150km or in space, what speed should it be so it can match the speed of the objects as they cross the disk of the moon in the video?

Do you know any trigonometry? Can you draw a triangle to describe the distances?

 

[mfb]

Let's say these objects were the Russian space force and 150 km above or in space and traveling at 100 knots.

They would fall down and exceed 100 knots within seconds. 100 knots is an airspeed: A speed where wings can keep you up. In space you just fall down.

Or for the objects to be 150km or in space, what speed should it be so it can match the speed of the objects as they cross the disk of the moon in the video?

But that's what I calculated! I used your speed to get a height. The same height leads to the same speed in reverse.

 

[lucas_]

They would fall down and exceed 100 knots within seconds. 100 knots is an airspeed: A speed where wings can keep you up. In space you just fall down.But that's what I calculated! I used your speed to get a height. The same height leads to the same speed in reverse.

They are likely balloons then.

At what height can balloons travel completely horizontally (after they reached the ceiling, and what's the ceiling of balloons how many miles up the air)?

At what distance should the balloons be shown as dots in the disk and what speed should they be moving to match the behavior in the video?

 

[lucas_]

They would fall down and exceed 100 knots within seconds. 100 knots is an airspeed: A speed where wings can keep you up. In space you just fall down.

You said "In space you just fall down"? But why do satellites were able to be either stationary or moving in space without falling down? I was talking about in stable orbit. So you simply mean 150 kilometers up still in escape velocity or height? What height are those satellites then?

The logical explanations are balloons. But if these were large objects and between the Earth and moon (such as these just for sake of illustration), they could be traveling at fast speed to cross the disk of the moon and appear just like in the video, right?

But that's what I calculated! I used your speed to get a height. The same height leads to the same speed in reverse.

 

[lucas_]

Was this filmed from the ground? As almost points, the altitude can't be determined.

And regardless of altitude these objects were flying incredibly slowly, not fast. That's why I'd consider a cluster of balloons in almost still air possible.

If these were space debris (or rocks) in between Earth and moon. Can't they move fast but appear slow when filmed at ground? When you mentioned the word "altitude", did it mean below the height of those satellites or with air/atmosphere?

 

[mfb]

At what height can balloons travel completely horizontally (after they reached the ceiling, and what's the ceiling of balloons how many miles up the air)?

At any distance, it depends on the balloon.
The speed depends on the distance, and given the multiple calculations that are now in the thread I'm sure you can calculate it for whatever numbers you like.

You said "In space you just fall down"? But why do satellites were able to be either stationary or moving in space without falling down? I was talking about in stable orbit. So you simply mean 150 kilometers up still in escape velocity or height? What height are those satellites then?

This is also something I discussed before: In low Earth orbit satellites need over 7 km/s to stay in orbit. In higher orbits the speed goes down and for a geostationary orbit it is somewhat similar to what we see here - but there the satellites are in sunlight and there are not enough to explain these dots. That also applies to everything else you ask about in space.

The logical explanations are balloons. But if these were large objects and between the Earth and moon (such as these just for sake of illustration), they could be traveling at fast speed to cross the disk of the moon and appear just like in the video, right?

No, the size of the object is completely irrelevant here.

 

[sophiecentaur]

The objects are in hard focus but the Moon is not. That suggests that they must be very close because a lens focussed at 'infinity' would make the Moon image as sharp as a satellite. Also, they are dark, which means they must be in the Earth's shadow. That would imply that they are either very close to Earth or the Moon is near - overhead; the actual time of the film is relevant here.

If the things were satellites then surely they would appear as very bright dots when they emerged from the Earth's shadow. Did anyone see and film them in that conditions?
The shapes are round and no wings are evident (they would surely be with that sharpness of focus) so I guess they would have to be a flight of balloons. If they were normal plastic envelopes then radar wouldn't see them.

OTOH, it looks very like a spoof!

 

[mfb]

The objects are in hard focus but the Moon is not.

I got a different impression. The video is just zoomed in - everything is smeared, the dark dots are not an exception.

At the time the second large group is close to the right edge of the Moon two of the objects are close together, you can see that their motion is not uniform.

Helium balloons sounds like the most plausible option to me, unless the dark spots are from video editing.

 

[lucas_]

At any distance, it depends on the balloon.
The speed depends on the distance, and given the multiple calculations that are now in the thread I'm sure you can calculate it for whatever numbers you like.This is also something I discussed before: In low Earth orbit satellites need over 7 km/s to stay in orbit. In higher orbits the speed goes down and for a geostationary orbit it is somewhat similar to what we see here - but there the satellites are in sunlight and there are not enough to explain these dots. That also applies to everything else you ask about in space.No, the size of the object is completely irrelevant here.

In other situations where there are large objects near the moon. It should behave like that moving slowly too but with shadows, right? At what angle or distance to the moon the shadows can not be visible but object is still seen?

Someday if we will have large sails across the moon. How should they look like or behave when video taken from the ground of earth?