Mushroom Cloud and Bow shock

[Nilesh]

What is the difference between Mushroom Cloud and Bow Shock ? Why it happens ? 

[Chyren S]

Mushroom cloud forms because of immense energy eruption in the lower atmosphere which is not able to expand because of surrounding atmosphere. When it shoots up, after a height space pressure try to compress the thermal energy coming from surface. As a result mushroom cloud formation is seen.

bow shock is different. It’s like a celestial object comes from the low density atmosphere to high density atmosphere or from a very cold space to a materialistic high temperature space, this temperature difference pushed to object to heat up. As the surrounding is space only, the thermal energy of fire (of this burning object) repels the space layers and hence the bow is formed. This creates a bow shock. 
both of them aren’t comparable.

[Philalethes]

If by "mushroom cloud" you mean the iconic cloud associated with large explosions, then the better question would be what the similarities are rather than the differences, since the two are very distinct phenomena. There's a somewhat semicircular shape (semidomal in three dimensions in reality) associated with both related to the balance between expansionary and compressive forces.

The shapes are distinct due to the forces involved in both cases; a mushroom cloud tends to maintain its shape until it gets high enough up, at which point it flattens out since the expansionary forces of its fireball can no longer push through the compressive forces of the layers of air above it, whereas the bow shock remains more or less in place and is rather met by the compressive force of the Solar wind from the other direction, which flattens it perpendicularly instead, bending it inwards at the edges due to Earth's magnetic field being less compressible near the geomagnetic equator.

Here are a couple of quick animations to illustrate the difference; first the spherical fireball of the explosion rising and being compressed after it moves far enough up:

Then the Solar wind meeting Earth's magnetosphere and compressing it more closer to the poles due to the magnetic field being less compressible near the geomagnetic equator, making it similar to how water flows around the bow of a ship:

So the overall difference between the two modes of compression is that in one case the compression takes place in direction of movement, while in the other the compression takes place perpendicular to the direction of movement. So while the shapes are distinct, there is a certain geometric relationship between them.

Just as an added caveat, these are of course extremely simplified models. The actual physics involved are much more complex, and there's a lot of movement not captured here.

Edited June 3, 2023 by Philalethes
caveat

[Nilesh]

9 hours ago, Chyren S said:

Mushroom cloud forms because of immense energy eruption in the lower atmosphere which is not able to expand because of surrounding atmosphere. When it shoots up, after a height space pressure try to compress the thermal energy coming from surface. As a result mushroom cloud formation is seen.

bow shock is different. It’s like a celestial object comes from the low density atmosphere to high density atmosphere or from a very cold space to a materialistic high temperature space, this temperature difference pushed to object to heat up. As the surrounding is space only, the thermal energy of fire (of this burning object) repels the space layers and hence the bow is formed. This creates a bow shock. 
both of them aren’t comparable.

Working force is the same. The different shape is due to the impact of angle. We notice bow shock other places too. Ok thank you for the reply.

8 hours ago, Philalethes said:

If by "mushroom cloud" you mean the iconic cloud associated with large explosions, then the better question would be what the similarities are rather than the differences, since the two are very distinct phenomena. There's a somewhat semicircular shape (semidomal in three dimensions in reality) associated with both related to the balance between expansionary and compressive forces.

The shapes are distinct due to the forces involved in both cases; a mushroom cloud tends to maintain its shape until it gets high enough up, at which point it flattens out since the expansionary forces of its fireball can no longer push through the compressive forces of the layers of air above it, whereas the bow shock remains more or less in place and is rather met by the compressive force of the Solar wind from the other direction, which flattens it perpendicularly instead, bending it inwards at the edges due to Earth's magnetic field being less compressible near the geomagnetic equator.

Here are a couple of quick animations to illustrate the difference; first the spherical fireball of the explosion rising and being compressed after it moves far enough up:

Then the Solar wind meeting Earth's magnetosphere and compressing it more closer to the poles due to the magnetic field being less compressible near the geomagnetic equator, making it similar to how water flows around the bow of a ship:

So the overall difference between the two modes of compression is that in one case the compression takes place in direction of movement, while in the other the compression takes place perpendicular to the direction of movement. So while the shapes are distinct, there is a certain geometric relationship between them.

Just as an added caveat, these are of course extremely simplified models. The actual physics involved are much more complex, and there's a lot of movement not captured here.

Thank you for reply. Everything is simple, we make it complex.

9 hours ago, Chyren S said:

Mushroom cloud forms because of immense energy eruption in the lower atmosphere which is not able to expand because of surrounding atmosphere. When it shoots up, after a height space pressure try to compress the thermal energy coming from surface. As a result mushroom cloud formation is seen.

bow shock is different. It’s like a celestial object comes from the low density atmosphere to high density atmosphere or from a very cold space to a materialistic high temperature space, this temperature difference pushed to object to heat up. As the surrounding is space only, the thermal energy of fire (of this burning object) repels the space layers and hence the bow is formed. This creates a bow shock. 
both of them aren’t comparable.

People also ask

Why do things catch fire in the atmosphere?

As meteors, shuttles, or capsules hit the atmosphere, they rub against the air at very high speeds, which makes them burn." 

Your Quote for above " a celestial object comes from the low density atmosphere to high density atmosphere or from a very cold space to a materialistic high temperature space, this temperature difference pushed to object to heat up.  " 

I think your example is more authentic. Because while we launch satellite rocket goes out from hot atmosphere to cold that's why it didn't catch fire at that high scape velocity of earth. Is it true ?

[Newbie]

Bow shock refers to a phenomenon that occurs when an object, such as a spacecraft or a celestial body, moves through a medium, typically a fluid or a plasma, at supersonic speeds. The term "bow shock" comes from its resemblance to the bow of a ship, which creates a similar effect when moving through water.

When an object moves through a medium at supersonic speeds, it creates a shock wave in front of it. The bow shock forms at the leading edge of this shock wave, where the surrounding medium is abruptly compressed and heated. The bow shock takes the shape of a curved surface that extends outward from the object's leading edge, resembling a bow or the arc of a circle.

The formation of a bow shock is a consequence of the object's supersonic motion. As the object moves faster than the speed of sound in the medium, it creates a region of compressed gas or plasma in front of it. This compressed region leads to an increase in pressure and temperature, causing the gas or plasma to slow down and change properties.

In astrophysics, bow shocks are commonly observed around celestial objects, such as stars, supernovae remnants, and even galaxies. For example, when a star moves through the interstellar medium, it creates a bow shock as it interacts with the surrounding gas and dust. These bow shocks can be visible as bright arcs or shells of emission, indicating the presence of a moving object.

Bow shocks also have practical applications in aerodynamics and spacecraft design. Understanding the formation and behavior of bow shocks is crucial for designing vehicles that can efficiently navigate through different mediums, such as air or planetary atmospheres.

In summary, bow shock refers to the curved shock wave that forms at the leading edge of an object moving at supersonic speeds through a fluid or plasma. It is characterized by a compression and heating of the surrounding medium, creating a distinctive arc-shaped structure.

N.

[Newbie]

A mushroom cloud is formed as a result of a powerful explosion, typically caused by a nuclear detonation or a large-scale conventional explosion. The distinctive shape of the cloud resembles that of a mushroom, with a thick stem and a bulbous, expanding cap.

The formation of a mushroom cloud can be understood through the following process:

Initial Blast: When a powerful explosion occurs, a tremendous amount of energy is released almost instantaneously. In the case of a nuclear detonation, this energy comes from the rapid release of nuclear forces and the subsequent chain reaction. In conventional explosions, the energy is generated by the combustion of a high explosive material.

Upward Motion: The explosion creates an intense shockwave that expands outward in all directions, including vertically. The initial blast wave rapidly propels the superheated air, debris, and gases upwards into the atmosphere.

Condensation: As the hot gases and debris rise, they displace the surrounding cooler air. This upward motion causes the hot gases to cool down, leading to a decrease in pressure and temperature. When the air cools sufficiently, the moisture present in the air starts to condense into visible water droplets, forming a dense cloud.

Cap Formation: The upward-moving hot gases eventually reach a point where they stop rising due to their own weight and the resistance of the surrounding air. At this point, the cloud starts to spread horizontally, forming the cap or head of the mushroom. The cap is composed of the condensed water droplets and the debris caught up in the initial explosion.

Stem Formation: Below the cap, the stem of the mushroom cloud is formed. It is created by the rising column of hot air and gases, which continue to expand and push the cloud upward. The stem can be thinner and more elongated compared to the cap.

The distinctive shape of the mushroom cloud is due to the interplay of various factors, including the initial explosion's energy release, the rapid expansion of gases, and the atmospheric conditions at the time of the explosion. The mushroom cloud's formation and appearance make it an iconic visual representation of a powerful explosion.

[Nilesh]

4 hours ago, Newbie said:

Bow shock refers to a phenomenon that occurs when an object, such as a spacecraft or a celestial body, moves through a medium, typically a fluid or a plasma, at supersonic speeds. The term "bow shock" comes from its resemblance to the bow of a ship, which creates a similar effect when moving through water.

When an object moves through a medium at supersonic speeds, it creates a shock wave in front of it. The bow shock forms at the leading edge of this shock wave, where the surrounding medium is abruptly compressed and heated. The bow shock takes the shape of a curved surface that extends outward from the object's leading edge, resembling a bow or the arc of a circle.

The formation of a bow shock is a consequence of the object's supersonic motion. As the object moves faster than the speed of sound in the medium, it creates a region of compressed gas or plasma in front of it. This compressed region leads to an increase in pressure and temperature, causing the gas or plasma to slow down and change properties.

In astrophysics, bow shocks are commonly observed around celestial objects, such as stars, supernovae remnants, and even galaxies. For example, when a star moves through the interstellar medium, it creates a bow shock as it interacts with the surrounding gas and dust. These bow shocks can be visible as bright arcs or shells of emission, indicating the presence of a moving object.

Bow shocks also have practical applications in aerodynamics and spacecraft design. Understanding the formation and behavior of bow shocks is crucial for designing vehicles that can efficiently navigate through different mediums, such as air or planetary atmospheres.

In summary, bow shock refers to the curved shock wave that forms at the leading edge of an object moving at supersonic speeds through a fluid or plasma. It is characterized by a compression and heating of the surrounding medium, creating a distinctive arc-shaped structure.

N.

Thank you for your detailed reply. The escape velocity of earth is about  11 km/s , why doesn't the rockets caught fire when they go out side of earth atmosphere ?

2 hours ago, Newbie said:

A mushroom cloud is formed as a result of a powerful explosion, typically caused by a nuclear detonation or a large-scale conventional explosion. The distinctive shape of the cloud resembles that of a mushroom, with a thick stem and a bulbous, expanding cap.

The formation of a mushroom cloud can be understood through the following process:

Initial Blast: When a powerful explosion occurs, a tremendous amount of energy is released almost instantaneously. In the case of a nuclear detonation, this energy comes from the rapid release of nuclear forces and the subsequent chain reaction. In conventional explosions, the energy is generated by the combustion of a high explosive material.

Upward Motion: The explosion creates an intense shockwave that expands outward in all directions, including vertically. The initial blast wave rapidly propels the superheated air, debris, and gases upwards into the atmosphere.

Condensation: As the hot gases and debris rise, they displace the surrounding cooler air. This upward motion causes the hot gases to cool down, leading to a decrease in pressure and temperature. When the air cools sufficiently, the moisture present in the air starts to condense into visible water droplets, forming a dense cloud.

Cap Formation: The upward-moving hot gases eventually reach a point where they stop rising due to their own weight and the resistance of the surrounding air. At this point, the cloud starts to spread horizontally, forming the cap or head of the mushroom. The cap is composed of the condensed water droplets and the debris caught up in the initial explosion.

Stem Formation: Below the cap, the stem of the mushroom cloud is formed. It is created by the rising column of hot air and gases, which continue to expand and push the cloud upward. The stem can be thinner and more elongated compared to the cap.

The distinctive shape of the mushroom cloud is due to the interplay of various factors, including the initial explosion's energy release, the rapid expansion of gases, and the atmospheric conditions at the time of the explosion. The mushroom cloud's formation and appearance make it an iconic visual representation of a powerful explosion.

Thank you for detailed reply. How much time does it take to make mushroom cloud ?  Now think about your various factor , how much time they have to play their role to make the mushroom cloud ?

[Newbie]

3 hours ago, Nilesh said:

Thank you for your detailed reply. The escape velocity of earth is about  11 km/s , why doesn't the rockets caught fire when they go out side of earth atmosphere ?

Thank you for detailed reply. How much time does it take to make mushroom cloud ?  Now think about your various factor , how much time they have to play their role to make the mushroom cloud ?

The time it takes for a mushroom cloud to appear after a nuclear explosion can vary depending on several factors, including the size and type of the nuclear weapon, the altitude of the detonation, and atmospheric conditions. Generally, a mushroom cloud forms within seconds to minutes after the detonation.

In an airburst explosion, where the nuclear device detonates above the ground, the mushroom cloud begins to form almost immediately after the detonation. The initial fireball created by the explosion rapidly rises and expands due to the intense heat and energy released. As it rises, it entrains surrounding air and debris, forming the characteristic mushroom-shaped cloud. This process typically occurs within a matter of seconds.

On the other hand, in a groundburst explosion, where the nuclear device detonates at or near the ground, the formation of the mushroom cloud may take slightly longer. The shockwave generated by the detonation initially creates an upward surge of debris and dust, followed by the characteristic mushroom-shaped cloud formation. This process may take a few seconds to minutes, depending on the specific conditions.

N.

When a rocket reaches escape velocity, it doesn't mean that the rocket's engines stop burning. In fact, the engines of a rocket burn throughout its entire journey into space. Escape velocity is simply the minimum velocity an object needs to attain to escape the gravitational pull of a celestial body, such as Earth.

The reason a rocket doesn't continue burning indefinitely after reaching escape velocity is due to the principle of conservation of energy. Once a rocket reaches its desired velocity, it can stop firing its engines and coast through space. This is because in the vacuum of space, there is no air resistance or friction to slow the rocket down.

In order to reach escape velocity, a rocket must overcome the gravitational force of the Earth, which requires a significant amount of energy. Once it reaches that velocity, the rocket is able to "coast" through space without the need for continuous thrust, as long as no other forces act upon it.

It's important to note that rockets often undergo multiple stages during their journey. Each stage typically consists of one or more rocket engines that provide the necessary thrust to propel the rocket. Once a stage has burned through its fuel, it is usually jettisoned, and the next stage takes over. This staging process allows the rocket to shed excess weight and become more efficient as it ascends into space.

N.

 

 

[Nilesh]

1 hour ago, Newbie said:

The time it takes for a mushroom cloud to appear after a nuclear explosion can vary depending on several factors, including the size and type of the nuclear weapon, the altitude of the detonation, and atmospheric conditions. Generally, a mushroom cloud forms within seconds to minutes after the detonation.

In an airburst explosion, where the nuclear device detonates above the ground, the mushroom cloud begins to form almost immediately after the detonation. The initial fireball created by the explosion rapidly rises and expands due to the intense heat and energy released. As it rises, it entrains surrounding air and debris, forming the characteristic mushroom-shaped cloud. This process typically occurs within a matter of seconds.

On the other hand, in a groundburst explosion, where the nuclear device detonates at or near the ground, the formation of the mushroom cloud may take slightly longer. The shockwave generated by the detonation initially creates an upward surge of debris and dust, followed by the characteristic mushroom-shaped cloud formation. This process may take a few seconds to minutes, depending on the specific conditions.

N.

When a rocket reaches escape velocity, it doesn't mean that the rocket's engines stop burning. In fact, the engines of a rocket burn throughout its entire journey into space. Escape velocity is simply the minimum velocity an object needs to attain to escape the gravitational pull of a celestial body, such as Earth.

The reason a rocket doesn't continue burning indefinitely after reaching escape velocity is due to the principle of conservation of energy. Once a rocket reaches its desired velocity, it can stop firing its engines and coast through space. This is because in the vacuum of space, there is no air resistance or friction to slow the rocket down.

In order to reach escape velocity, a rocket must overcome the gravitational force of the Earth, which requires a significant amount of energy. Once it reaches that velocity, the rocket is able to "coast" through space without the need for continuous thrust, as long as no other forces act upon it.

It's important to note that rockets often undergo multiple stages during their journey. Each stage typically consists of one or more rocket engines that provide the necessary thrust to propel the rocket. Once a stage has burned through its fuel, it is usually jettisoned, and the next stage takes over. This staging process allows the rocket to shed excess weight and become more efficient as it ascends into space.

N.

 

 

 

 

 

 

Thank you for your reply.

My point is simple what is the speed or velocity the rocket  has to maintain to get out of the earth's gravitational force and  that is 11km/s it has to maintain. No matter how it gets. And at that velocity the  air friction is working on it so it should burn , if am not wrong ?

[Newbie]

31 minutes ago, Nilesh said:

Thank you for your reply.

My point is simple what is the speed or velocity the rocket  has to maintain to get out of the earth's gravitational force and  that is 11km/s it has to maintain. No matter how it gets. And at that velocity the  air friction is working on it so it should burn , if am not wrong ?

This is because in the vacuum of space, there is no air resistance or friction to slow the rocket down as I have already mentioned.

Kind regards 

Newbie
 

[Philalethes]

9 hours ago, Newbie said:

Cap Formation: The upward-moving hot gases eventually reach a point where they stop rising due to their own weight and the resistance of the surrounding air. At this point, the cloud starts to spread horizontally, forming the cap or head of the mushroom. The cap is composed of the condensed water droplets and the debris caught up in the initial explosion.

Well put. To add to that something I didn't mention in my previous reply to keep it simple, there's also the additional fact that the sphere of the fireball itself will suck in air at the bottom and form vortices around the middle (along the bottom-top axis) of it, causing it to take on the semicircular shape of the mushroom cap even before significant compression occurs, as per the illustration offered on the Wikipedia page on the matter:

So even when the fireball itself "should" be more or less spherical due to not much compression having occurred yet it takes on that distinct hemispherical shape instead:

But then of course as you say compression occurs more and more as it rises, flattening out the cap much like a mushroom does as it grows; in fact, to me it seems to unfold almost exactly like the lifespan of a fly agaric mushroom (A. muscaria, although I bet there are plenty of "button"-like mushrooms following a similar pattern).

I'm sure none of this is news to you, but hopefully it's informative for Nilesh.

[Nilesh]

1 hour ago, Newbie said:

This is because in the vacuum of space, there is no air resistance or friction to slow the rocket down as I have already mentioned.

Kind regards 

Newbie
 

and for the case of meteoroids for shuttles  vacuum doesn't work , and it's get burn. Hope you may clear my thoughts.

Thank you. 

[Philalethes]

38 minutes ago, Nilesh said:

and for the case of meteoroids for shuttles  vacuum doesn't work , and it's get burn. Hope you may clear my thoughts.

Thank you. 

They don't burn in space; they burn as they enter/reenter the atmosphere. When a meteoroid enters the atmosphere we call the ensuing streak of light a meteor, and if any parts of it survive and reach the ground we call those parts meteorites.

Edited June 5, 2023 by Philalethes

[Newbie]

36 minutes ago, Nilesh said:

and for the case of meteoroids for shuttles  vacuum doesn't work , and it's get burn. Hope you may clear my thoughts.

Thank you. 

Nilesh I’m not sure of the point you are trying to make but consider the atmosphere surrounding the earth.

The atmosphere surrounding the Earth is not divided into distinct layers with clear boundaries. However, it can be generally categorized into several regions based on their characteristics. Here is a description of the atmospheric gradient from Earth to space:

Troposphere: This is the lowest layer of the atmosphere, extending from the Earth's surface up to an average altitude of about 8 to 15 kilometers (5 to 9 miles). The troposphere is where weather phenomena occur, and it contains most of the Earth's atmospheric mass. The temperature generally decreases with increasing altitude in this layer.

Stratosphere: Above the troposphere lies the stratosphere, which extends from the tropopause (the boundary between the troposphere and stratosphere) to an altitude of approximately 50 kilometers (31 miles). In the stratosphere, the temperature generally increases with altitude due to the presence of the ozone layer, which absorbs and scatters a significant amount of the Sun's ultraviolet radiation.

Mesosphere: Beyond the stratosphere is the mesosphere, which stretches from the stratopause (the boundary between the stratosphere and mesosphere) to an altitude of around 85 kilometers (53 miles). In the mesosphere, the temperature decreases again with increasing altitude.

Thermosphere: The thermosphere is the next layer, extending from the mesopause (the boundary between the mesosphere and thermosphere) to an altitude of about 600 kilometers (372 miles) or more. The temperature in this region can reach extremely high values due to the absorption of intense solar radiation. However, the air density is extremely low, and it would not feel hot to a human observer.

Exosphere: Finally, the exosphere is the outermost region of the Earth's atmosphere. It gradually transitions into the vacuum of space, with no clear boundary. In this region, the air density is extremely low, and individual gas particles can travel significant distances without colliding with other particles. The temperature is not well-defined in the exosphere since there is very little molecular interaction.

It's important to note that the boundaries between these atmospheric layers are not sharp, and there is some overlap and variation based on factors such as latitude, weather conditions, and solar activity. The specific altitudes mentioned here are approximate values and can vary depending on the reference source.

A spacecraft is not going to burn as it leaves the Earth’s atmosphere and travels into space.

However a returning spacecraft is an entirely different matter. The angle of re entry is critical and such craft are fitted with heat shields to protect the astronauts and the craft. Even so it is very uncomfortable for those aboard for a number of minutes.

Shuttles and meteorites? One would hope they don’t occur together. It’s an unlikely event.

 

1 hour ago, Philalethes said:

Well put. To add to that something I didn't mention in my previous reply to keep it simple, there's also the additional fact that the sphere of the fireball itself will suck in air at the bottom and form vortices around the middle (along the bottom-top axis) of it, causing it to take on the semicircular shape of the mushroom cap even before significant compression occurs, as per the illustration offered on the Wikipedia page on the matter:

So even when the fireball itself "should" be more or less spherical due to not much compression having occurred yet it takes on that distinct hemispherical shape instead:

But then of course as you say compression occurs more and more as it rises, flattening out the cap much like a mushroom does as it grows; in fact, to me it seems to unfold almost exactly like the lifespan of a fly agaric mushroom (A. muscaria, although I bet there are plenty of "button"-like mushrooms following a similar pattern).

I'm sure none of this is news to you, but hopefully it's informative for Nilesh.

Mushrooms are amazing in the way they appear overnight from nowhere.

Agreed the pic is very similar to the mushroom you describe. 😊

N.

[Philalethes]

20 minutes ago, Newbie said:

Mushrooms are amazing in the way they appear overnight from nowhere.

Agreed the pic is very similar to the mushroom you describe.

Yeah, it never ceases to surprise me what you can find one morning in the woods that definitely wasn't there the night before. From what I've gathered it's due to growing much in the same way like bamboo, preparing cells in advance and then rapidly filling them up with water.

I guess that's enough mushroom talk for now on my part, even if it's very marginally related to the topic; one last image because it really does illustrate both the effects mentioned and why it's called a mushroom cloud:

[ insert bomb sound of your own making ]

[Nilesh]

2 hours ago, Newbie said:

Nilesh I’m not sure of the point you are trying to make but consider the atmosphere surrounding the earth.

The atmosphere surrounding the Earth is not divided into distinct layers with clear boundaries. However, it can be generally categorized into several regions based on their characteristics. Here is a description of the atmospheric gradient from Earth to space:

Troposphere: This is the lowest layer of the atmosphere, extending from the Earth's surface up to an average altitude of about 8 to 15 kilometers (5 to 9 miles). The troposphere is where weather phenomena occur, and it contains most of the Earth's atmospheric mass. The temperature generally decreases with increasing altitude in this layer.

Stratosphere: Above the troposphere lies the stratosphere, which extends from the tropopause (the boundary between the troposphere and stratosphere) to an altitude of approximately 50 kilometers (31 miles). In the stratosphere, the temperature generally increases with altitude due to the presence of the ozone layer, which absorbs and scatters a significant amount of the Sun's ultraviolet radiation.

Mesosphere: Beyond the stratosphere is the mesosphere, which stretches from the stratopause (the boundary between the stratosphere and mesosphere) to an altitude of around 85 kilometers (53 miles). In the mesosphere, the temperature decreases again with increasing altitude.

Thermosphere: The thermosphere is the next layer, extending from the mesopause (the boundary between the mesosphere and thermosphere) to an altitude of about 600 kilometers (372 miles) or more. The temperature in this region can reach extremely high values due to the absorption of intense solar radiation. However, the air density is extremely low, and it would not feel hot to a human observer.

Exosphere: Finally, the exosphere is the outermost region of the Earth's atmosphere. It gradually transitions into the vacuum of space, with no clear boundary. In this region, the air density is extremely low, and individual gas particles can travel significant distances without colliding with other particles. The temperature is not well-defined in the exosphere since there is very little molecular interaction.

It's important to note that the boundaries between these atmospheric layers are not sharp, and there is some overlap and variation based on factors such as latitude, weather conditions, and solar activity. The specific altitudes mentioned here are approximate values and can vary depending on the reference source.

A spacecraft is not going to burn as it leaves the Earth’s atmosphere and travels into space.

However a returning spacecraft is an entirely different matter. The angle of re entry is critical and such craft are fitted with heat shields to protect the astronauts and the craft. Even so it is very uncomfortable for those aboard for a number of minutes.

Shuttles and meteorites? One would hope they don’t occur together. It’s an unlikely event.

 

Mushrooms are amazing in the way they appear overnight from nowhere.

Agreed the pic is very similar to the mushroom you describe. 😊

N.

" A spacecraft is not going to burn as it leaves the Earth’s atmosphere and travels into space. " Your Quote 

The reason behind it going from hotter area to cooler area , loosing body heat  heat but maintaining velocity. In the case of meteorites they gain heat -273 deg ( or much less ) to 0 deg , heat gain by body 273 deg , body temperature makes it burn. 

Thank you. 

3 hours ago, Philalethes said:

Well put. To add to that something I didn't mention in my previous reply to keep it simple, there's also the additional fact that the sphere of the fireball itself will suck in air at the bottom and form vortices around the middle (along the bottom-top axis) of it, causing it to take on the semicircular shape of the mushroom cap even before significant compression occurs, as per the illustration offered on the Wikipedia page on the matter:

So even when the fireball itself "should" be more or less spherical due to not much compression having occurred yet it takes on that distinct hemispherical shape instead:

But then of course as you say compression occurs more and more as it rises, flattening out the cap much like a mushroom does as it grows; in fact, to me it seems to unfold almost exactly like the lifespan of a fly agaric mushroom (A. muscaria, although I bet there are plenty of "button"-like mushrooms following a similar pattern).

I'm sure none of this is news to you, but hopefully it's informative for Nilesh.

Sure, but it's not the reason behind it. 

Thank you.

[Philalethes]

21 minutes ago, Nilesh said:

The reason behind it going from hotter area to cooler area , loosing body heat  heat but maintaining velocity. In the case of meteorites they gain heat -273 deg ( or much less ) to 0 deg , heat gain by body 273 deg , body temperature makes it burn. 

You don't understand. The heating has nothing to do with the temperature of the atmosphere. A meteor would not be burning or glowing at 0° C just because it was colder before. In reality meteors are heated up to almost 2000 kelvins; it happens because of atmospheric drag. Space Shuttle reentry can reach temperatures of up to 1750 kelvins.

The reason why objects entering the atmosphere from outside it are heated up more is because they have higher speeds when they encounter the atmosphere; drag is a function of speed and density (and a few other factors). When exiting the atmosphere they don't gain that much speed until they're already far enough up where the density is low and they leave the atmosphere. The moment when there is maximum drag is known as max q, and the drag at that moment will be much lower for anything exiting the atmosphere than entering it for that reason.

21 minutes ago, Nilesh said:

Sure, but it's not the reason behind it. 

Yes, it is one of the two main reasons for why the cloud takes on the appearance of a mushroom. It causes the distinct shape of the cap, while the compression flattens it out.

Edited June 5, 2023 by Philalethes

[Nilesh]

15 hours ago, Philalethes said:

You don't understand. The heating has nothing to do with the temperature of the atmosphere. A meteor would not be burning or glowing at 0° C just because it was colder before. In reality meteors are heated up to almost 2000 kelvins; it happens because of atmospheric drag. Space Shuttle reentry can reach temperatures of up to 1750 kelvins.

The reason why objects entering the atmosphere from outside it are heated up more is because they have higher speeds when they encounter the atmosphere; drag is a function of speed and density (and a few other factors). When exiting the atmosphere they don't gain that much speed until they're already far enough up where the density is low and they leave the atmosphere. The moment when there is maximum drag is known as max q, and the drag at that moment will be much lower for anything exiting the atmosphere than entering it for that reason.

Yes, it is one of the two main reasons for why the cloud takes on the appearance of a mushroom. It causes the distinct shape of the cap, while the compression flattens it out.

if heating has nothing to do , than why we put our hands near fire place in cold season ? Any way, my understanding is clear about, what is happening with meteors , why bow shock have it's structure and why mushroom cloud appear so soon. 

Thank you for your all replies . 

Edited June 6, 2023 by Nilesh

[Philalethes]

5 hours ago, Nilesh said:

if heating has nothing to do , than why we put our hands near fire place in cold season ?

When you put your hands near a fireplace your hands are heated from thermal energy produced through combustion. When a meteor enters the atmosphere its kinetic energy compresses the air in front of it, massively increasing its temperature; there is then heat transfer from this hot air to the meteor.

In the first case the source of the thermal energy is conversion of chemical energy via combustion, and in the second case the source of the thermal energy is conversion of kinetic energy via compression.

Thus we see that the reason for temperature increase in those two cases are quite different; and in any case neither of them have anything to do with simply going from cold to hot, because like I mentioned there wouldn't be any glowing or burning of the meteor at 0° C just because it was much colder before, much like taking a piece of wood out of the freezer and leaving it on a bench won't cause it to catch fire.

5 hours ago, Nilesh said:

my understanding clear what is happening with meteors

To me that does not seem to be the case at all, since you still erroneously seem to think meteors are heated due to the temperature differential between the atmosphere and outside the atmosphere, which is not true.

Edited June 6, 2023 by Philalethes

[Archmonoth]

19 hours ago, Nilesh said:

if heating has nothing to do , than why we put our hands near fire place in cold season ? Any way, my understanding is clear about, what is happening with meteors , why bow shock have it's structure and why mushroom cloud appear so soon. 

 

For some clarity here is a wiki description of both the Bow Shock and the Mushroom Cloud:

 

Bow shock - Wikipedia

"In astrophysics, a bow shock occurs when the magnetosphere of an astrophysical object interacts with the nearby flowing ambient plasma such as the solar wind."

 

To me, the interaction with plasma is a distinct characteristic of a Bow Shock.

 

Mushroom cloud - Wikipedia

"Mushroom clouds result from the sudden formation of a large volume of lower-density gases at any altitude, causing a Rayleigh–Taylor instability. "

 

To me, the difference in density (from altitude) with gases is a distinct characteristic of a mushroom cloud.

 

 

Plasma used to be considered ionized gas, but this is no longer the case:

Plasma (physics) - Wikipedia

 

Edited June 7, 2023 by Archmonoth

[Nilesh]

18 hours ago, Philalethes said:

When you put your hands near a fireplace your hands are heated from thermal energy produced through combustion. When a meteor enters the atmosphere its kinetic energy compresses the air in front of it, massively increasing its temperature; there is then heat transfer from this hot air to the meteor.

In the first case the source of the thermal energy is conversion of chemical energy via combustion, and in the second case the source of the thermal energy is conversion of kinetic energy via compression.

Thus we see that the reason for temperature increase in those two cases are quite different; and in any case neither of them have anything to do with simply going from cold to hot, because like I mentioned there wouldn't be any glowing or burning of the meteor at 0° C just because it was much colder before, much like taking a piece of wood out of the freezer and leaving it on a bench won't cause it to catch fire.

To me that does not seem to be the case at all, since you still erroneously seem to think meteors are heated due to the temperature differential between the atmosphere and outside the atmosphere, which is not true.

"you still erroneously seem to think meteors are heated due to the temperature differential between the atmosphere and outside the atmosphere, which is not true."  Yes "Meteors are heated due to the temperature differential. " You can't change the truth.

Thank You.

[Newbie]

52 minutes ago, Nilesh said:

"you still erroneously seem to think meteors are heated due to the temperature differential between the atmosphere and outside the atmosphere, which is not true."  Yes "Meteors are heated due to the temperature differential. " You can't change the truth.

Thank You.

Seem to be repeating but anyways…

When a meteor enters the Earth's atmosphere, it experiences a rapid increase in temperature due to the intense friction between the meteor and the surrounding air molecules. This process is known as atmospheric heating or ablation.

As the meteor travels through the atmosphere at high speeds, typically tens of kilometers per second, it compresses the air molecules in front of it, creating a high-pressure region. The air molecules in this region get rapidly heated due to the compression, and the temperature can reach thousands of degrees Celsius. This heating is similar to what happens when you compress the air in a bicycle pump—its temperature rises.

Additionally, the meteor's surface is subjected to immense pressure from the collision with the air molecules. This pressure generates a shock wave that further increases the temperature of the meteor. The shock wave compresses and heats the air in front of the meteor, creating a glowing plasma around it called a plasma sheath.

The combination of compression, friction, and shock heating causes the outer layers of the meteor to vaporize and melt, releasing an incandescent trail of glowing gases and ions behind it. This glowing trail is commonly known as a meteor or shooting star.

It's worth noting that not all meteors survive the intense heating caused by atmospheric entry. Fragments can break off or disintegrate entirely due to the extreme conditions. Meteors that manage to reach the Earth's surface are called meteorites as has been mentioned Nilesh please just accept this 😊

[Philalethes]

1 hour ago, Nilesh said:

"you still erroneously seem to think meteors are heated due to the temperature differential between the atmosphere and outside the atmosphere, which is not true."  Yes "Meteors are heated due to the temperature differential. " You can't change the truth.

Thank You.

Try reading the whole sentence: "you still erroneously seem to think meteors are heated due to the temperature differential between the atmosphere and outside the atmosphere"; that is not the case at all. The temperature differential is created locally in front of and around the meteor as it compresses the air in front of it, and has nothing to do with the difference in temperature between the atmosphere and space, it has to do with the difference in density. This is why you see the meteor and the air immediately surrounding it and trailing behind it glow.

Edited June 7, 2023 by Philalethes

[Nilesh]

6 hours ago, Newbie said:

Seem to be repeating but anyways…

When a meteor enters the Earth's atmosphere, it experiences a rapid increase in temperature due to the intense friction between the meteor and the surrounding air molecules. This process is known as atmospheric heating or ablation.

As the meteor travels through the atmosphere at high speeds, typically tens of kilometers per second, it compresses the air molecules in front of it, creating a high-pressure region. The air molecules in this region get rapidly heated due to the compression, and the temperature can reach thousands of degrees Celsius. This heating is similar to what happens when you compress the air in a bicycle pump—its temperature rises.

Additionally, the meteor's surface is subjected to immense pressure from the collision with the air molecules. This pressure generates a shock wave that further increases the temperature of the meteor. The shock wave compresses and heats the air in front of the meteor, creating a glowing plasma around it called a plasma sheath.

The combination of compression, friction, and shock heating causes the outer layers of the meteor to vaporize and melt, releasing an incandescent trail of glowing gases and ions behind it. This glowing trail is commonly known as a meteor or shooting star.

It's worth noting that not all meteors survive the intense heating caused by atmospheric entry. Fragments can break off or disintegrate entirely due to the extreme conditions. Meteors that manage to reach the Earth's surface are called meteorites as has been mentioned Nilesh please just accept this 😊

In which Earth's atmosphere layer we find Hydrogen Gas, and what is it's temperature there ? 

[Sam Warfel]

This is not the topic of these forums, even if it was a respectful and productive conversation. Any further discussion must take place in Unproven Theories, if it takes place at all.