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A hard sphere is bad, no no, it has to be not hard, it has to be flexible. More thsn that - it has to be active and actively interact with shock wave, and extract energy.

A of a25bedc5-3d09-41b8-82fb-ea6c353d75ae is a good answer, because it suggests an energy extraction mechanisms for that whole situation.

More than that, they might use the supernova blast and for energy and for building that super QC system. They will have plenty of material, rich with heavy elements, in volumes hard to find in other parts of universe and more important hard to collect in one place (takes long time, or special circumstances, like a super massive black hole in middle of galaxy).

Even more important than energy is that they will have a black hole (if the chosen star is good), which can be used for extracting energy from around stars and from remains of this star, with much more greater yield. (10-100 more), at $\small 0.5 \times mc^2$

And those objects (Supernova remains + BH or NS) are valuable resources, so even if you have one, you might want to have more of them, and they are rare enough. This place might start to be place of force on a local scale (1000's ly). Yes, you might get cold remains of such event in past, still valuable but it's a looong journey to power, but with all or most of remains of super nova it will be really very attractive place in therms of energy and matter, and it makes great sense to overcome all difficulties on the way to obtain it.

This antimatter spear part also isn't bad too, might work, there will be a lot of radiations, but shield from planets might work. No need to annihilate everything on way, just slight change of impulse to form cone. Move planet, all planets, probably rob near by systems for all heavy materials (from stars too) (not necessary), add more H He to the star to make it blast when you need it, not when it wish(at least ability to tune process a bit, and capture more neutrons, easy to burn thermonuclear fuel is also useful stuff, not easy to make, fast).

Just a regular matter spear will work same way as antimatter specially if you accelerate it to 20000 km/s(not necessary, just saves some mass in exchange to energy needed), if you wish to protect a planet, but is more cheaper then antimatter, and easier to obtain. Same way as Ablation. So saving a planet as a bioreactor is possible.

Distance is good not only because energy density $\small \sim 1/r^2$, but blast wave is not energy-velocity monochromatic, so this way it will grow more gradual at bigger distance.

Also some separation of materials by atom weights might happen, because of acceleration mechanisms (light pressure and such), we do not need all elements equal, some we need first, and it's nice to use that possibly situation for our advantage.

Also this way we might focus jets in to nearby stars where we have also systems waiting for actions, which might focus that energy and disassemble star using that energy, this way we might convert nearby stars to clouds (1000's of them) which we might to transport to our BH, later.

With the help of the BH and the stars around and tools this wave can be stopped in reasonable time.

The remains of the supernova, in the form of a BH or maybe a neutron star, in worse case (or it just another possibility also good one, I even do not know what to choose neutron start(NS) or BH, give me both) will be great help in stopping wave.

Also a great way is to launch expansion across galaxy at 0.99c speeds, or fly to SMBH for goals like this answer Why would a civilisation choose to inhabit a single enormous vessel instead of maintaining interstellar colonies?

So yes, supernovas and possibilities they offer are really attractive, but people plz plz do it good this time, not like it was with planets (ships searching planet with live and bananas to eat, 1960-70-80-...-novadays) - let's do it right this time))

• A supernova starting from 10 mass of sun, so at 100'000 A.U. average amount of matter flow trough sphere from star will be 0.00704 kg/m² (or one cubic centimeter of iron), and if wave will spread during 15 year of travel, in a way let say it begins at 15y mark and ends (kinda) at 16y mark - this value per second will be much less then that (just high speed dust), but more constant pressure. We might do lot of things with that density flow at 20000 km/s or even more, even in case of hypernova (10 times more mass).

• One of your priorities is to isolate remain BH or NS as soon as possible, to prevent matter being lost. It's more important then even catching all shock wave, because it might make BH and NS inaccessible for out tools, for longer period of times then we wish.

• Isolating and lifting matter around a BH (NS) is a great way to utilize some energy of shock wave, this way we may catch more and easier.
  Again, clearing the area around the BH (NS) is important - it's our anchor for operation.

• A spear is good way to clear path to internal, short after the blast, before wave will come to soap bubble sphere.

• A sphere do not have to be tick, it's not a wall stopping shock wave - it's like mesh-net with soap bubbles

• 15 years is more than enough time to cool down for shock wave Supernova, Light curves.

• Very important moment, this Supernova, Energy output :

Only 0.1 foe (1foe=10⁴⁴J) or less in form of gamma rays and other forms of radiation, even for hypernova, most energy is in form of kinetic energy of ejected mass.

• Another important moment, result of blast are heavy elements, and after some years they already below melting points, and to contain them in compact form, soap bubbles need no force for that. So even parts we did not stopped may be kept compact in travel, so we will catch them as single piece later

• More important we do not need soap bubbles, at all, just channels where we forming sticks from that shock wave media, yes, at 20000 km/s speed. Most of elements are Al, Si and below. R-process

• How big, by mass, would that sphere has to be?

Good question. In the "move a planet"-question, there was a pressure of gases, and sphere's used there are rather small, and they needed 1% by mass for active surface(shell) with 1bar pressure inside. Efficiency of solution is better with size, so with 100'000 (30 millions km) times bigger it will be 1%/100'000, so 1/10'000'000 mass of star. (Volume grows $\small \sim r^3$, thickness and mass $\small \sim r^2$, so mass of content grows faster them mass of shell.)

But in the case of supernova remains there is no pressure to contain (solids, with high meting point, mostly, pretty cool after 15 years), we have just press dust in to solid sticks fast enough, so even less then that. (Yes, we will catch them later.)

So exchanging one Gas giant for carbon in star (until there is some carbon and it didn't burned out) is good idea and that's enough. So probably even no need to rob nearby systems.

Those stick we pressed, they will need some help to collect together during flight and focus their force on near by systems to evaporate stars, and yes we have to add enough of active material to accomplish that, but I think we still good with one GG.

• Hypernova are not so good, as I wished, they might implode without ejecting materials, not so good, we wish ejected material.

• 20'000 km/s is from Normal Type Ia:
  An outwardly expanding shock wave is generated, with matter reaching velocities on the order of 5,000–20,000 km/s, or roughly 3% of the speed of light.

• All energy of the blast, all 10⁴⁶J (hypernova) might be stored in form of kinetic energy around black hole(potentially, not sure about tool, BH 30km radius may be too small for tool to do that, will leak - small hole, SMBH is better in that sense), but not around NS

• Do not sell or exchange information with them if they are farther then 2000ly, and you have doubts you will get from them what you agreed.

• Ask for 10% of QC power

• If they are closer then 300ly and problem is today, sell it any way(are trustworthy or not) ask for 30%.

• If Venus is disassembled and they are closer then 1000ly, ask for the whole system, they might solve what they wish and take planet if they wish, and sell in case if they trustworthy.

• If they did't payed after event, it can mean 2 types of problem. One is big - they are not trustworthy, it will be The Pain, if even possible at all to get them from that system. Second problem is not a problem, needs to check plans.

A hard sphere is bad, no no, it has to be not hard, it has to be flexible. More than that - it has to be active and actively interact with the shock wave, and extract energy.

A of a25bedc5-3d09-41b8-82fb-ea6c353d75ae is a good answer because it suggests an energy extraction mechanisms for that whole situation.

More than that, they might use the supernova blast and for energy and for building that super QC system. They will have plenty of material, rich with heavy elements, in volumes hard to find in other parts of the universe and more importantly, hard to collect in one place (takes a long time, or special circumstances, like a super massive black hole in the middle of a galaxy).

Even more important than energy is a possibility of having a black hole (if the chosen star is good) as the result of such explosion. Using which it is possible to extract energy from the matter they can obtain in the location - around stars and from remains of this star and other star systems. Matter of energy conversion could have a good efficiency like $\small 0.5 \times mc^2$(if my calculations and assumptions are correct) and potentially have a much greater yield than the explosion of supernovae itself over time.

And those objects (Supernova remains + BH or NS) are valuable resources, so even if you have one, you might want to have more of them, and they are rare enough. This place might begin to be a place of force on a local scale (1000's ly) for them. Yes, you might get cold remains of such event of in the past, it will still valuable but could be a looong journey to power, but with all or most of remains of super nova it will be really very attractive place in therms of energy and matter, and it makes great sense to overcome all difficulties on the way to obtain it and handle the situation in more sophisticated way.

This antimatter spear part also isn't bad too, might work, there will be a lot of radiations, but a shield for a planet might work too. No need to annihilate everything, just slight change of impulse to form a shadow cone. Move planet, all planets, probably rob near by systems for all heavy materials (from stars too) (not necessary), add more H He to the star to make it blast when you need it, not when it wishes(at least ability to tune process a bit, and capture more neutrons, easy to burn thermonuclear fuel is also useful stuff, not easy to make fast and in quantity).

Just a regular matter spear will work the same way as antimatter especially if you accelerate it to 20000 km/s(not necessary, just saves some mass in exchange for energy requirements) in case if you wish to protect a planet, and it is cheaper then antimatter, and easier to obtain. Same way as Ablation. So saving a planet as a bioreactor is possible. (also wave of matter from such blast is a plasma, thus using magnetic field helps to protect such spear and reduce its ablation losses)

Distance is good not only because energy density decreases proportionally to $\small \sim 1/r^2$, but also because blast wave is not energy-velocity monochromatic, so this way it will grow more gradual at a bigger distance.

Also, some separation of materials by atom weights might happen, because of acceleration mechanisms (light pressure and such), we do not need all elements equal, some we need first, and it's would nice to use the possible situation for our advantage.

Also, this way we might focus jets into nearby stars where we have also systems waiting for actions, by focusing shockwave into Hydrogen Helium jets(after removing heavy elements, and because we might not need light elements). This will focus the energy of the blast and allow star lifting using that energy when those jets arrive in star systems around. This way we might convert nearby stars to clouds (1000's of them) which we might to transport to our BH, later. Star lifting or complete disassembly and converting a star to a cloud by using the energy of a star itself is a million's million's year process and because of that using energy of supernovae in form of those jets to speed up the process is a good idea. There are also other tricks which could be possible with those jets, as redistribution of the impulse of that shockwave matter in jets and keep our shell momentum intact(or near so) which is one of the great problems in the situation. By using the energy of the incoming wave, to accelerate some part of it to let's say near 1c velocity. It helps to leave a significant portion of the matter from the star in its system, 98% of it, and focus the energy of the blast in 2% of the matter and near 1c speed, thus it will arrive to systems we would like to disassemble much faster, 50 times faster than it would be if we just focus 20'000 km/s jets as it is. Sure efficiency will not be 100%, but it could be closer to that than one could expect in the situation.

With the help of the BH and the stars around and tools, this wave can be stopped in reasonable time.

The remains of the supernova, in the form of a BH or maybe a neutron star, in worse case (or it just another possibility also good one, I even do not know what to choose neutron start(NS) or BH, give me both) will be a great help in stopping the wave.

Also, a great way is to launch expansion across galaxy at 0.99c speeds or fly to SMBH for goals like this answer Why would a civilization choose to inhabit a single enormous vessel instead of maintaining interstellar colonies?

So yes, supernovas and possibilities they offer are really attractive, but people plz plz do it well this time, not like it was with planets (ships searching planet with live and bananas to eat, 1960-70-80-...-novadays) - let's do it right this time))

• A supernova starting from 10 mass of sun, so at 100'000 A.U. average amount of matter flow trough sphere from star will be 0.00704 kg/m² (or one cubic centimeter of iron), and if wave will spread during 15 year of travel, in a way let say it begins at 15y mark and ends (kinda) at 16y mark - this value per second will be much less then that (just high speed dust), but more constant pressure. We might do a lot of things with that density flow at 20000 km/s or even more, even in case of hypernova (10 times more mass).

• One of your priorities is to isolate remain BH or NS as soon as possible, to prevent matter being lost in accretion processes. It's more important than even catching all of the shock wave, because it might make BH and NS inaccessible for out tools in the future, for a longer period of times then we might wish.

• Isolating and lifting matter around a BH (NS) is a great way to utilize some energy of shock wave, this way we may catch more and easier.
  Again, clearing the area around the BH (NS) is important - it's our anchor for the operation.

• A spear is a good way to clear path to internal olume/guts of the explosion, shortly after the blast, before wave will come to soap bubble sphere.

• A sphere does not have to be tick, it's not a wall stopping shock wave - it's like mesh-net with soap bubbles

• 15 years is more than enough time to cool down for shock wave Supernova, Light curves.

• Very important moment, this Supernova, Energy output :

Only 0.1 foe (1foe=10⁴⁴J) or less in form of gamma rays and other forms of radiation, even for hypernova, most energy is in form of kinetic energy of ejected mass.

• Another important moment, the result of the blast are heavy elements, and after some years they already below melting points, and to contain them in compact form, soap bubbles do not need to apply any force to do that. So even parts we did not stopped may be kept compact in travel, so we will catch them as single piece later

• More important we do not need soap bubbles, at all, just channels where we forming sticks from that shock wave media, yes, at 20000 km/s speed. Most of elements are Al, Si and below. R-process

• How big, by mass, would that sphere has to be?

Good question. In the "move a planet"-question, there was a pressure of gases, and sphere's used there are rather small, and they needed 1% by mass for active surface(shell) with 1bar pressure inside. The efficiency of the solution is better with size, so with 100'000 (30 million km) times bigger, it will be 1%/100'000, so 1/10'000'000 mass of the star. (Volume grows $\small \sim r^3$, thickness, and mass $\small \sim r^2$, so the mass of content grows faster than the mass of the shell.)

But in the case of supernova remains there is no pressure to contain (solids, with a high melting point, mostly, pretty cool after 15 years), we have just press dust into solid sticks fast enough, so even less than that. (Yes, we will catch them later, in nearby star systems.)

So exchanging one Gas giant for carbon in the star prior the blast (until there is some carbon and it didn't burned out) is a good idea and that's enough. So probably even no need to rob nearby systems.

Those sticks we pressed, they will need some help to collect together during flight and focus their force on near by systems to evaporate stars, and yes we have to add enough of active material to accomplish that, but I think we still good with one GG.

• Hypernova are not so good, as I wished, they might implode without ejecting materials, not so good, we wish ejected material.

• 20'000 km/s is from Normal Type Ia:
  An outwardly expanding shock wave is generated, with matter reaching velocities on the order of 5,000–20,000 km/s, or roughly 3% of the speed of light.

• All energy of the blast, all 10⁴⁶J (hypernova) might be stored in form of kinetic energy around black hole(potentially, not sure about tool, BH 30km radius may be too small for tool to do that, will leak - too small BH, SMBH is better in that sense), but not around NS

• Do not sell or exchange information with them if they are farther than 2000ly away, and you have doubts you will get from them what you agreed for.

• Ask for 10% of QC power

• If they are closer then 300ly and the problem is let's say today(our time), sell it anyway(are trustworthy or not) ask for 30%.

• If Venus is disassembled and they are closer than 1000ly, ask for the whole system, they might solve what they wish and take planet if they wish, and sell in case if they trustworthy(but take a hefty price, do not be cheap in the case, in all of those cases).

• If they didn't pay after the event, it can mean 2 types of problem. One is big - they are not trustworthy, it will be The Pain, if even possible at all to get them from that system. The second problem is not a problem, needs to check plans.

Actually interesting answer from a25bedc5-3d09-41b8-82fb-ea6c353d75ae (link to answer)

it does not fit to comment and some points are valuable as answer, so it's kind clarification for A above.

Hard sphere is bad, no no, it have to be not hard, it have to be flexible, more then that, it have to be active and actively interact with shock wave, and extract energy.

Shock wave speed is around 20'000km/s. So sphere have to have more complex structure then just plain sphere. It have to have some inward parts, which will accelerate to that speed in direction to wave, and shape incoming wave. And with interaction shape areas of wave, without destruction of those parts(parts which interact with wave, have velocity in direction from star, heading to outside of sphere with relatively same speed) - jets inside jets, to let areas of wave pass the main grid(slip in-between) and begin to extract kinetic energy, heat energy from that shock wave. (extraction have to begin even earlier, at that shaping wave time, with de-accelerating and accelerating again part which was moved to star)

mad skillzz about jet-jet:

• yes, I did not forgot about conservation of momentum, but it best way I could to draw a picture.
• funny note, if you will hover near planet - not orbiting, you might spend GG of fuel and fly nowhere, be still around planet, not so easy but just funny note.

A of a25bedc5-3d09-41b8-82fb-ea6c353d75ae is good answer because it suggests energy extraction mechanisms for that whole situation.

Also QC of those aliens, it can't be on the planet. It's just question of efficiency. If they have reversible bits energy, they maybe do not need much of that supernova energy. If they consume and dissipate energy in process of making calculations, placing this computer on the planet have no sense - it can't consume that energy in reasonable time, to make calculations of that size.

More then that, they might use supernova blast and for energy and for building that super QC system. They will have plenty of material, rich with heavy elements, in voulmes hard to find in other parts of universe and more important hard to collect in one place (takes long time, or special circumstances, like super massive black hole in middle of galaxy)

Even More important then energy is, they will have black hole(if chosen star is good), which can be used for extracting energy from around stars and from remains of this star, with much more greater yield. (10-100 more), at $\small 0.5 \times mc^2$

And those objects(Supernova remains+BH or NS) are valuable resources, so even if you have one, you might want to have more of them, and they are rare enough. This place might start to be place of force on local scale(1000's ly). Yes, you might get cold remains of such event in past, still valuable but it's looong journey to power, but with all or most of remains of super nova it will be really very attractive place in therms of energy and matter, and it makes great sense to overcome all difficulties on the way to obtain it.

Those guys are adventurers nature: Everything what do not rips universe apart, makes us stronger

This way supernova blast is indeed, great opportunity, which might be exploited.

This antimatter spear part also isn't bad too, might work, there will be a lot of radiations, but shield from planets might work. No need to annihilate everything on way, just slight change of impulse to form cone. Move planet, all planets, probably rob near by systems for All heavy materials(from stars too)(not necessary), add more H He to the star to make it blast when you need it, not when it wish(at least ability to tune process a bit, and capture more neutrons, easy to burn thermonuclear fuel is also useful stuff, not easy to make, fast)

Just regular matter spear will work same way as antimatter specially if you accelerate it to 20000 km/s(not necessary, just saves some mass in exchange to energy needed), if you wish to protect a planet, but is more cheaper then antimatter, and easier to obtain. Same way as Ablation. So saving planet as bioreactor is possible.

Any way, better to move planet away, at 100000 a.u., same distance as sphere, flash will come in 1.7 years, wave in 15-20years. Sphere of that size can dissipate(at 1200K)(or convert to energy) Hypernova 1e46J blast in one year. Strongly suggest to read my answer about planet moving, "sphere" can be done such way.

This way we do not need to catch all remains at once, only part we can and need atm, everything else we will catch in other star systems. As backup plan, if power exceed our expectations.

With help of BH and stars around and tools this wave can be stopped in reasonable time.

Remains of supernova, in form of BH or maybe neutron star, in worse case (or it just another possibility also good one, I even do not know what to choose neutron start(NS) or BH, give me both) will be great help in stopping wave.

Also great way to launch expansion across galaxy at 0.99c speeds, or fly to SMBH for goals like this answer Why would a civilisation choose to inhabit a single enormous vessel instead of maintaining interstellar colonies?

• supernova starting from 10 mass of sun, so at 100000 a.u. average amount of matter flow trough sphere from star will be 0.00704 kg/m² (or one cubic centimeter of iron), and if wave will spread during 15 year of travel, in a way let say it begins at 15y mark and ends(kinda)at 16y mark - this value per second will be much less then that(just high speed dust), but more constant pressure. We might do lot of things with that density flow at 20000 km/s or even more, even in case of hypernova(10 times more mass).

• one of priorities is to isolate remain BH or NS as soon as possible, to prevent matter being lost. It's more important then even catching all shock wave, because it might make BH and NS inaccessible for out tools, for longer period of times then we wish.

• isolating and lifting matter around BH(NS) is great way to utilize some energy of shock wave, this way we may catch more and easier.
  Again clearing area around BH(NS) is important it's our anchor for operation.

• Spear is good way to clear path to internal, short after the blast, before wave will come to soap bubble sphere.

• sphere do not have to be tick, it's not a wall stopping shock wave, it's like mesh-net with soap bubbles

• 15 years is more the enough time to cool down for shock wave Supernova, Light curves.

• Very important moment, this Supernova, Energy output :

• another important moment, result of blast are heavy elements, and after some years they already below melting points, and to contain them in compact form, soap bubbles need no force for that. So even parts we did not stopped may be kept compact in travel, so we will catch them as single piece later

• More important we do not need soap bubbles, at all, just channels where we forming sticks from that shock wave media, yes, at 20000 km/s speed. Most of elements are Al, Si and below. R-process

• How big, by mass, that sphere have to be?

Good question, in move planet question, there was a pressure of gases, and sphere's used there are rather small, and they needed 1% by mass for active surface(shell) with 1bar pressure inside. Efficiency of solution is better with size, so with 100000 (30 millions km) times bigger it will be 1%/100000, so 1/10'000'000 mass of star. (volume grows $\small \sim r^3$, thickness and mass $\small \sim r^2$, so mass of content grows faster them mass of shell)

But in case of supernova remains there is no pressure to contain(solids, with high meting point, mostly, pretty cool after 15y), we have just press dust in to solid sticks fast enough, so even less then that. (yes, we will catch them later)

So exchange one Gas giant for carbon in star (until there is some carbon and it didn't burned out) is good idea and that's enough. So probably even no need to rob nearby systems.

• Hypernova are not so good, as I wished, they might implode without ejecting materials, not so good, we wish ejected material.

• 20000 km/s is from Normal Type Ia:
  An outwardly expanding shock wave is generated, with matter reaching velocities on the order of 5,000–20,000 km/s, or roughly 3% of the speed of light.

• all energy of the blast, all 10⁴⁶J (hypernova) might be stored in form of kinetic energy around black hole(potentially, not sure about tool, BH 30km radius may be too small for tool to do that, will leak - small hole, SMBH is better in that sense), but not around NS

• Do not sell or exchange information with them if they are farther then 2000ly, and you have doubts you will get from them what you agreed.

• Ask for 10% of QC power

• if they are closer then 300ly and problem is today, sell it any way(are trustworthy or not) ask for 30%.

• if Venus is disassembled and they are closer then 1000ly, ask for whole system, they might solve what they wish and take planet if they wish, and sell in case if they trustworthy.

• if they did't payed after event, it can mean 2 types of problem. One is big - they are not trustworthy, it will be The Pain, if even possible at all to get them from that system. Second problem is not a problem, needs to check plans.

Actually interesting answer from a25bedc5-3d09-41b8-82fb-ea6c353d75ae (link to answer).

This does not fit into a comment and some points are valuable as an answer, so it's kind of a clarification for A above.

A hard sphere is bad, no no, it has to be not hard, it has to be flexible. More thsn that - it has to be active and actively interact with shock wave, and extract energy.

Shock wave speed is around 20'000km/s. So the sphere has to have a more complex structure then just a plain sphere. It has to have some inward parts, which will accelerate to that speed in the direction of the wave, and shape the incoming wave. And with the interaction of the shape areas of the wave, without destruction of those parts  (the parts which interact with the wave, have the velocity in direction from star, heading to the outside of the sphere with relatively same speed) - jets inside jets, to let areas of the wave pass the main grid  (slip in-between) and begin to extract kinetic energy, heat energy from that shock wave. (The extraction has to begin even earlier, at that shaping wave time, with de-accelerating and accelerating again part which was moved to star.)

Mad skillzz about jet-jet:

• Yes, I did not forget about conservation of momentum, but it's the best way I could to draw a picture.
• Funny note: if you will hover near planet - not orbiting, you might spend GG of fuel and fly nowhere, be still around the planet. Not so easy, but just a funny note.

A of a25bedc5-3d09-41b8-82fb-ea6c353d75ae is a good answer, because it suggests an energy extraction mechanisms for that whole situation.

Also QC of those aliens, it can't be on the planet. It's just a question of efficiency. If they have reversible bits energy, they maybe do not need much of that supernova energy. If they consume and dissipate energy in the process of making calculations, placing this computer on the planet makes no sense - it can't consume that energy in a reasonable time, to make calculations of that size.

More than that, they might use the supernova blast and for energy and for building that super QC system. They will have plenty of material, rich with heavy elements, in volumes hard to find in other parts of universe and more important hard to collect in one place (takes long time, or special circumstances, like a super massive black hole in middle of galaxy).

Even more important than energy is that they will have a black hole  (if the chosen star is good), which can be used for extracting energy from around stars and from remains of this star, with much more greater yield. (10-100 more), at $\small 0.5 \times mc^2$

And those objects  (Supernova remains + BH or NS) are valuable resources, so even if you have one, you might want to have more of them, and they are rare enough. This place might start to be place of force on a local scale  (1000's ly). Yes, you might get cold remains of such event in past, still valuable but it's a looong journey to power, but with all or most of remains of super nova it will be really very attractive place in therms of energy and matter, and it makes great sense to overcome all difficulties on the way to obtain it.

Those guys have an adventurer's nature: Everything that does not rip the universe apart, makes us stronger!

This way the supernova blast is indeed, great opportunity, which might be exploited.

This antimatter spear part also isn't bad too, might work, there will be a lot of radiations, but shield from planets might work. No need to annihilate everything on way, just slight change of impulse to form cone. Move planet, all planets, probably rob near by systems for all heavy materials  (from stars too)  (not necessary), add more H He to the star to make it blast when you need it, not when it wish(at least ability to tune process a bit, and capture more neutrons, easy to burn thermonuclear fuel is also useful stuff, not easy to make, fast).

Just a regular matter spear will work same way as antimatter specially if you accelerate it to 20000 km/s(not necessary, just saves some mass in exchange to energy needed), if you wish to protect a planet, but is more cheaper then antimatter, and easier to obtain. Same way as Ablation. So saving a planet as a bioreactor is possible.

Anyway, better to move the planet away, at 100'000 A.U., the same distance as the sphere, the flash will come in 1.7 years, the wave in 15-20 years. A sphere of that size can dissipate  (at 1200K)  (or convert to energy) Hypernova 1e46J blast in one year. Strongly suggest to read my answer about planet moving, "sphere" can be done such way.

This way we do not need to catch all remains at once, only part we can and need atm, everything else we will catch in other star systems. As a backup plan, if power exceed our expectations.

With the help of the BH and the stars around and tools this wave can be stopped in reasonable time.

The remains of the supernova, in the form of a BH or maybe a neutron star, in worse case (or it just another possibility also good one, I even do not know what to choose neutron start(NS) or BH, give me both) will be great help in stopping wave.

Also a great way is to launch expansion across galaxy at 0.99c speeds, or fly to SMBH for goals like this answer Why would a civilisation choose to inhabit a single enormous vessel instead of maintaining interstellar colonies?

• A supernova starting from 10 mass of sun, so at 100'000 A.U. average amount of matter flow trough sphere from star will be 0.00704 kg/m² (or one cubic centimeter of iron), and if wave will spread during 15 year of travel, in a way let say it begins at 15y mark and ends  (kinda) at 16y mark - this value per second will be much less then that  (just high speed dust), but more constant pressure. We might do lot of things with that density flow at 20000 km/s or even more, even in case of hypernova  (10 times more mass).

• One of your priorities is to isolate remain BH or NS as soon as possible, to prevent matter being lost. It's more important then even catching all shock wave, because it might make BH and NS inaccessible for out tools, for longer period of times then we wish.

• Isolating and lifting matter around a BH  (NS) is a great way to utilize some energy of shock wave, this way we may catch more and easier.
  Again, clearing the area around the BH  (NS) is important - it's our anchor for operation.

• A spear is good way to clear path to internal, short after the blast, before wave will come to soap bubble sphere.

• A sphere do not have to be tick, it's not a wall stopping shock wave - it's like mesh-net with soap bubbles

• 15 years is more than enough time to cool down for shock wave Supernova, Light curves.

• Very important moment, this Supernova, Energy output :

• Another important moment, result of blast are heavy elements, and after some years they already below melting points, and to contain them in compact form, soap bubbles need no force for that. So even parts we did not stopped may be kept compact in travel, so we will catch them as single piece later

• More important we do not need soap bubbles, at all, just channels where we forming sticks from that shock wave media, yes, at 20000 km/s speed. Most of elements are Al, Si and below. R-process

• How big, by mass, would that sphere has to be?

Good question. In the "move a planet"-question, there was a pressure of gases, and sphere's used there are rather small, and they needed 1% by mass for active surface(shell) with 1bar pressure inside. Efficiency of solution is better with size, so with 100'000 (30 millions km) times bigger it will be 1%/100'000, so 1/10'000'000 mass of star. (Volume grows $\small \sim r^3$, thickness and mass $\small \sim r^2$, so mass of content grows faster them mass of shell.)

But in the case of supernova remains there is no pressure to contain  (solids, with high meting point, mostly, pretty cool after 15 years), we have just press dust in to solid sticks fast enough, so even less then that. (Yes, we will catch them later.)

So exchanging one Gas giant for carbon in star (until there is some carbon and it didn't burned out) is good idea and that's enough. So probably even no need to rob nearby systems.

• Hypernova are not so good, as I wished, they might implode without ejecting materials, not so good, we wish ejected material.

• 20'000 km/s is from Normal Type Ia:
  An outwardly expanding shock wave is generated, with matter reaching velocities on the order of 5,000–20,000 km/s, or roughly 3% of the speed of light.

• All energy of the blast, all 10⁴⁶J (hypernova) might be stored in form of kinetic energy around black hole(potentially, not sure about tool, BH 30km radius may be too small for tool to do that, will leak - small hole, SMBH is better in that sense), but not around NS

• Do not sell or exchange information with them if they are farther then 2000ly, and you have doubts you will get from them what you agreed.

• Ask for 10% of QC power

• If they are closer then 300ly and problem is today, sell it any way(are trustworthy or not) ask for 30%.

• If Venus is disassembled and they are closer then 1000ly, ask for the whole system, they might solve what they wish and take planet if they wish, and sell in case if they trustworthy.

• If they did't payed after event, it can mean 2 types of problem. One is big - they are not trustworthy, it will be The Pain, if even possible at all to get them from that system. Second problem is not a problem, needs to check plans.

Actually interesting answer from a25bedc5-3d09-41b8-82fb-ea6c353d75ae (link to answer)

Any way, better to move planet away, at 100000 a.u., same distance as sphere, flash will come in 1.7 years, wave in 15-20years. Sphere of that size can dissipate(at 1200K)(or convert to energy) Hypernova 1e46J blast in one year. Strongly suggest to read my answer about planet moving, "sphere" can be done such way.

Also great way to launch expansion across galaxy at 0.99c speeds, or fly to SMBH for goals like this answer Why would a civilisation choose to inhabit a single enormous vessel instead of maintaining interstellar colonies?

Actually interesting answer from a25bedc5-3d09-41b8-82fb-ea6c353d75ae (link to answer)

Any way, better to move planet away, at 100000 a.u., same distance as sphere, flash will come in 1.7 years, wave in 15-20years. Sphere of that size can dissipate(at 1200K)(or convert to energy) Hypernova 1e46J blast in one year. Strongly suggest to read my answer about planet moving, "sphere" can be done such way.

Also great way to launch expansion across galaxy at 0.99c speeds, or fly to SMBH for goals like this answer Why would a civilisation choose to inhabit a single enormous vessel instead of maintaining interstellar colonies?