Tunguska - Related Question

[Vexer]

I just watched an amazing UFO-industry DVD about the Tunguska thing. How it was an alien spaceship.

 

But here's my serious question: are there *any* circumstances in which a -natural- infalling object can

"change direction" while coming to Earth? I don't mean *appearing* to change direction, I mean actually.

 

I think; "certainly not". (But it's been brought to my attention that I don't know everything).

 

 

 

 

You don't need to trash the alien spaceship idea, or "eyewitness" accounts that the object changed direction.

I'm not interested in that. Not here, anyway. Just the above question.

[Moontanman]

I just watched an amazing UFO-industry DVD about the Tunguska thing. How it was an alien spaceship.

 

But here's my serious question: are there *any* circumstances in which a -natural- infalling object can

"change direction" while coming to Earth? I don't mean *appearing* to change direction, I mean actually.

 

I think; "certainly not". (But it's been brought to my attention that I don't know everything).

 

 

 

 

You don't need to trash the alien spaceship idea, or "eyewitness" accounts that the object changed direction.

I'm not interested in that. Not here, anyway. Just the above question.

 

 

I think the problem here is that you are assuming a UFO show is inherently accurate. The initial reports did indeed seem to indicate the object had changed direction but that has been shown to be an artifact of eye witness accounts being given many years after the fact. But, to answer your question directly, if the object did indeed make a course correction it would indicate, to me at least, that the object was indeed artificial, others can correct me if i am wrong but I see no natural means for such an object to make change in direction. The Tunguska event was always one of my favorites and i followed it very closely from the time i was 12 years old or so.

[Turtle]

I just watched an amazing UFO-industry DVD about the Tunguska thing. How it was an alien spaceship.

 

But here's my serious question: are there *any* circumstances in which a -natural- infalling object can

"change direction" while coming to Earth? I don't mean *appearing* to change direction, I mean actually.

 

I think; "certainly not". (But it's been brought to my attention that I don't know everything).

 

 

 

 

You don't need to trash the alien spaceship idea, or "eyewitness" accounts that the object changed direction.

I'm not interested in that. Not here, anyway. Just the above question.

 

"change direction" is kinda' ambiguous in the context of Tunguska. what is the nature of the direction change you have in mind? all-in-all the laws of motion prevail. (minimum speed of a meteor is ~11kms/23,760 mph; max is ~72 kms/155,520 mph)it has been shown by experiment that an air burst from an object with an inclined trajectory forms the "butterfly" pattern seen in the downed trees at Tunguska, and the lack of any crater or intact "large" pieces of the incoming object reinforces this as the explanation for the event. in this context the constituent parts undergo many direction changes during the break-up, as well as state changes of matter.

 

without regard to the veracity of alien spacecraft, they would be no less subject to these constraints.

[Guest MacPhee]

Suppose an incoming object from space, has a spherical shape. It will just plunge straight down through the Earth's atmosphere, going in a straight trajectory. Obviously the atmosphere will slow down the object - as a result of increasing air-resistance. But the air-resistance will act on all sides of the spherical object equally. So the object will not deviate, just keep going in a straight line, until it hits the ground.

 

What if the object has a roughly non-spherical shape? Like an irregular-shaped lump of rock. The asymmetrical shape, will cause uneven air-resistance pressures. These uneven outside forces will probably make the rock tumble, but shouldn't result in it changing course significantly.

 

The only way an incoming object can make a gross change of course, is if it's:

 

1. Powered internally, with engines able to thrust it into a changed trajectory; and/or -

 

2. Possessed of a highly unnatural non-spherical shape - such a flat, saucer-like disc. If such a disc entered the atmosphere edgeways, then slid a bit sideways, asymmetric air-resistance could certainly cause the disc to flip over, and crash in a fiery explosion.

 

If the above reasoning is valid, then surely Tunguska is hard to explain as a natural event?

[Moontanman]

Again I will point out that the "change of direction" is a very weak observation. No one interviewed eye witnesses until many years after the fact. I have the book "The Fire Came By" and in it they expound heavily on the change of direction as evidence of their main point that the Tunguska object was artificial, in fact they insinuate the object was heading for a major city but exploded before it could get there.

 

The change in direction has been explained by the disorientation of the eyewitnesses at the time or an artifact of of the eyewitnesses being widely separated.

 

I think the Tunguska event suffers greatly from the fact that it was years before any outside observers managed to make it to the extremely remote location of the event.

 

in some ways it seems the people who did indeed investigate it were victims of their times. The Soviet scientist who first went there was convinced it was an exploded alien space craft.

 

Western scientists were automatically just as sure it could not have been, I'm not sure we will ever know for sure but none of the available evidence confirms an alien space craft and can be explained by natural phenomena.

Edited July 2, 2012 by Moontanman

[Turtle]

Suppose an incoming object from space, has a spherical shape. It will just plunge straight down through the Earth's atmosphere, going in a straight trajectory.

 

this is not the case. in space the object's path is an orbit that is a curved line and once trapped by earth's gravity the line is further curved. meteors can strike earth at nearly any angle. the trajectory may appear straight to an observer because of the speed.

 

 

 

Obviously the atmosphere will slow down the object - as a result of increasing air-resistance. But the air-resistance will act on all sides of the spherical object equally. So the object will not deviate, just keep going in a straight line, until it hits the ground.

 

the 'air resistance' does not act on all sides equally. the front of the object compresses atmospheric gasses -which is what causes the heating-, while the back side of the object experiences lower pressures.

 

ESTIMATING THE DRAG COEFFICIENTS OF METEORITES FOR ALL MACH NUMBER REGIMES.

...This best fit drag profile was used in a program created to model the descent of meteoritic fragments through the atmosphere. During these tests the fragments were assumed to be spherical meteoroids. We will present results comparing the trajectories of bolides using a drag coefficient of a constant value of 0.7, and also as drag as a function of Mach number. The difference between these two drag profiles will affect the range of the bolides and the shape of their trajectories. ...

 

 

What if the object has a roughly non-spherical shape? Like an irregular-shaped lump of rock. The asymmetrical shape, will cause uneven air-resistance pressures. These uneven outside forces will probably make the rock tumble, but shouldn't result in it changing course significantly.

 

at supersonic entry speeds (which all meteors must possess), the object will either break apart or align the long axis to the trajectory. any tumbling of the main body can only occur at subsonic speeds.

 

If the above reasoning is valid, then surely Tunguska is hard to explain as a natural event?

 

your reasoning is invalid and there is no difficulty explaining the event as natural.

[Guest MacPhee]

Thanks Turtle, for your post #6. The points it contains have corrected and clarified my thinking - I'm obliged.

 

Just to pick up on one thing, though - about a spherical object plunging straight down through the Earth's atmosphere. Here I had in mind, the old 1960's space capsules - the Soviet "Vostok", and the US "Mercury", "Gemini", and "Apollo".

 

As you know, the Soviet "Vostok" was a crude spherical object. Just like a cannon-ball. So when it re-entered the atmosphere, it fell down fast, in a ballistic trajectory. This subjected the on-board Cosmonaut to high G-forces, something like 9 or 10G.

 

Whereas the US capsules had a more sophisticated "cone-shape". This meant, that by pointing the blunt-end of the cone at suitable angles during re-entry, the capsules could be steered about, and so come down more slowly. Which reduced the G-forces on the Astronaut. This was such an obvious advantage, that of course, the Soviets copied the idea, and their next generation capsule - the "Soyuz" - had a blunt-end (and nearly half a century later, the Soyuz is still the most advanced spacecraft on the planet - what happened to the Space-Age?)

 

As regards the Tunguska event, the mystery seems to be: "Where's the meteorite debris on the ground?" It's like the hijacked airliner which supposedly hit the Pentagon, but mysteriously left no significant aircraft debris. Both events remain enigmatic.

[Turtle]

Thanks Turtle, for your post #6. The points it contains have corrected and clarified my thinking - I'm obliged.

 

my pleasure. it's what they pay me the big bucks for.

 

Just to pick up on one thing, though - about a spherical object plunging straight down through the Earth's atmosphere. Here I had in mind, the old 1960's space capsules - the Soviet "Vostok", and the US "Mercury", "Gemini", and "Apollo".

 

As you know, the Soviet "Vostok" was a crude spherical object. Just like a cannon-ball. So when it re-entered the atmosphere, it fell down fast, in a ballistic trajectory. This subjected the on-board Cosmonaut to high G-forces, something like 9 or 10G.

 

Whereas the US capsules had a more sophisticated "cone-shape". This meant, that by pointing the blunt-end of the cone at suitable angles during re-entry, the capsules could be steered about, and so come down more slowly. Which reduced the G-forces on the Astronaut. This was such an obvious advantage, that of course, the Soviets copied the idea, and their next generation capsule - the "Soyuz" - had a blunt-end (and nearly half a century later, the Soyuz is still the most advanced spacecraft on the planet - what happened to the Space-Age?)

 

some more clarification is needed here. first, none of the capsules you mention do any steering once they enter the atmosphere and as falling objects, they all by definition follow ballistic trajectories.

 

...

2. (Physics / General Physics) denoting or relating to the flight of projectiles after power has been cut off, moving under their own momentum and the external forces of gravity and air resistance

...

 

Vostok (spacecraft)

...

Reentry

 

The Vostok capsule had limited thruster capability. As such, the reentry path and orientation could not be controlled after the capsule had separated from the engine system. This meant that the capsule had to be protected from reentry heat on all sides, thus explaining the spherical design (as opposed to Project Mercury's conical design), which allowed for maximum volume while minimizing the external surface. Some control of the capsule reentry orientation was possible by way of positioning of the heavy equipment to offset the vehicle center of gravity, which also maximized the chance of the cosmonaut surviving g-forces while in a horizontal position. Even then, the cosmonaut experienced 8 to 9g.

...

 

As regards the Tunguska event, the mystery seems to be: "Where's the meteorite debris on the ground?" It's like the hijacked airliner which supposedly hit the Pentagon, but mysteriously left no significant aircraft debris. Both events remain enigmatic.

 

:doh: that is all pseudo-scientific conspiracy theory bullwash. the aircraft aside for some other thread, the lack of debris at Tunguska is well explained by the dynamics of supersonic meteors. understand that you have no experience by which to judge what happens to objects traveling 20,000+ miles per hour. it is not billiard balls, or bullets by any stretch of the imagination.

 

anyway, here's an abstract in support of my Tunguska debris assertion.

Could the Tunguska debris survive the terminal flare?

Planetary and Space Science, v. 46, p. 261-268.

 

The purpose of this paper is to show that lack of residual meteorites is typical for a fall of a stony or carbonaceous bolide tens of meters in size. A Tunguska-sized body penetrates deep into the atmosphere and is broken into a great deal of fragments the maximum size of which is smaller than 10 cm. Numerical simulations of analogous problems show that the fragments are separated from each other at a stage of dramatic deceleration of the bolide. Computations made here give that 3-10 cm stony fragments fully ablate either inside or outside the fireball due to high radiation flux. Only if the fragments accidentally gain significant lateral velocities at altitudes above 15 km, could their ponderable remnants reach the ground at 5-10 km from the explosion epicenter. Vaporized material of the impactor does not touch the ground and moves upward along the wake.

 

PS mind you that i do not mean to say that a "straight down", i.e. ~90º meteor hit is not possible. in such a case we can quickly find some example transit times from entry into the atmosphere to impact.

 

taking the minimum meteor speed of 23,000 mph and the "meteor-depth" of the atmosphere as 60 miles : ( earlier source )

23,000mph = 383.33mpm = 6.38mps: 60m/6.38 = 9.4 seconds

 

maximum speed:

155,520mph = 2592mpm = 43.2mps: 60m/43.2 = 1.38 seconds

Edited July 5, 2012 by Turtle

[Vexer]

My thanks to all those who replied.

 

 

Moontanman, nothing you said addressed my Opening Post. Read it again. For example, you wrote, “I think the problem here is that you are assuming a UFO show is inherently accurate.”

 

Obviously, I’m not. Re-read the opening post.

 

 

 

Turtle; you wrote; ”…what is the nature of the direction change you have in mind? “

 

The obvious kind.

 

 

MacPhee offered this: Possessed of a highly unnatural non-spherical shape - such a flat, saucer-like disc. If such a disc entered the atmosphere edgeways, then slid a bit sideways, asymmetric air-resistance could certainly cause the disc to flip over, and crash in a fiery explosion.

 

Could that be?

 

He continued: “If the above reasoning is valid, then surely Tunguska is hard to explain as a natural event?”

 

I’m just asking one single question.

 

 

 

 

Moontanman, you wrote:

 

“Again I will point out that the "change of direction" is a very weak observation…”

 

I will repeat part of my opening post: You don't need to trash the alien spaceship idea, or "eyewitness" accounts that the object changed direction. I'm not interested in that. Not here, anyway. Just answer the above question.

 

 

Thanks for MacPhee for trying to answer my question.

[Moontanman]

My thanks to all those who replied.

 

 

Moontanman, nothing you said addressed my Opening Post. Read it again. For example, you wrote, “I think the problem here is that you are assuming a UFO show is inherently accurate.”

 

Obviously, I’m not. Re-read the opening post.

 

 

 

Turtle; you wrote; ”…what is the nature of the direction change you have in mind? “

 

The obvious kind.

 

 

MacPhee offered this: Possessed of a highly unnatural non-spherical shape - such a flat, saucer-like disc. If such a disc entered the atmosphere edgeways, then slid a bit sideways, asymmetric air-resistance could certainly cause the disc to flip over, and crash in a fiery explosion.

 

Could that be?

 

He continued: “If the above reasoning is valid, then surely Tunguska is hard to explain as a natural event?”

 

I’m just asking one single question.

 

 

 

 

Moontanman, you wrote:

 

“Again I will point out that the "change of direction" is a very weak observation…”

 

I will repeat part of my opening post: You don't need to trash the alien spaceship idea, or "eyewitness" accounts that the object changed direction. I'm not interested in that. Not here, anyway. Just answer the above question.

 

 

Thanks for MacPhee for trying to answer my question.

 

 

I did answer your question.

 

I think the problem here is that you are assuming a UFO show is inherently accurate. The initial reports did indeed seem to indicate the object had changed direction but that has been shown to be an artifact of eye witness accounts being given many years after the fact. But, to answer your question directly, if the object did indeed make a course correction it would indicate, to me at least, that the object was indeed artificial, others can correct me if i am wrong but I see no natural means for such an object to make change in direction. The Tunguska event was always one of my favorites and i followed it very closely from the time i was 12 years old or so.

 

If you had bothered to read my entire post you would have seen that.

[CraigD]

... here's my serious question: are there *any* circumstances in which a -natural- infalling object can

"change direction" while coming to Earth? I don't mean *appearing* to change direction, I mean actually.

Practically all bodies in the solar system are constantly changing direction, because they follow paths determined by the gravitational attraction of the Sun, planets, and smaller bodies. In the case of bodies that enter the Earth’s atmosphere – meteorites and the more common meteors – this force doesn’t cease, but their paths become more complicated to calculate, because they become affected by aerodynamic drag forces.

 

Most bodies that enter the Earth’s atmosphere – meteors – change direction very radically, because they disintegrate into small particles that drift in the atmosphere, each particle following its own path, drifting great distance with the wind, increasing and decreasing in altitude before eventually reaching the ground. The 1908 Tunguska event you mention watching a DVD about, Vexer, is believed to have been a meteor, disintegrating in a powerful explosion at an altitude of 5 to 10 km. Floating dust believed to have come from it was observed for several months at locations far from Tunguska, Russia. It appears that no large bodies remained after the explosion, as several searches have found evident dust from the meteor, but no impact craters or meteorite remnants.

 

Because large meteoroids like 1908 Tunguska can, in principle, not explode into tiny dust particles, but split into irregular-shaped bodies, it’s conceivable that such a breakup might produce a body with a shape that would aerodynamically steer it, like a maneuvering airplane. However, this scenario strikes me as having a low probability, as does such a surviving fragment having the proper shape to aero-steer in a stable way very much from the path of the original, ovoid body – a “one in a million” (or less) likely occurrence.

 

In short, a body observed to enter the Earth’s atmosphere, then maneuver like an aircraft, is, I think, almost certain to be an aero-space vehicle. Since the only know aero-space vehicles weren’t flown until the 1960s, if something were flying around like this in 1908, it would, by definition, be an unidentified flying object, were it a either a meteor fragment or an artificial object.

[katsisco]

Wouldn't it have to have a massive charge to have exploded into dust? So was it equally antimatter and matter? Unlike our strange planet that seems to have lost that balance and is more matter?

Or alternatively it could have been more energy than matter. Like a CME that retains its energy and is shaped by our atmosphere into a 'ball lightening?' Lots of possibilities far beyond the aliens.

[Moontanman]

Wouldn't it have to have a massive charge to have exploded into dust? So was it equally antimatter and matter? Unlike our strange planet that seems to have lost that balance and is more matter?

Or alternatively it could have been more energy than matter. Like a CME that retains its energy and is shaped by our atmosphere into a 'ball lightening?' Lots of possibilities far beyond the aliens.

 

 

No object could be made of both matter and anti matter and exist, it would self annihilate instantly. It has been theorized that the Tunguska object was an anti-matter body and that it annihilated on contact with Earth's atmosphere. The evidence does not support this contention.

 

The most likely scenario is that is was a comet or other body that exploded due to mechanical stress and the heat of reentry. This effect is seen routinely by orbiting satellites when meteors explode in the upper atmosphere but are too small to affect the surface of the earth.

[Vexer]

Thanks Craig. To cut your post into once sentence: maybe there was a fragmentation effect (upon sustained impact with the atmosphere) that sent visible fragments off in different directions. (And you doubt this in this case).