你现在的想法就是抬杠
太空真的是空的嗎
版主： huangchong
#21 Re: 太空真的是空的嗎
及昭宗被轼，携其族往依王审知，终身不食梁䘵。捐馆日，留一箧缄鐍甚密。家人意为珍玩，发之，唯得烧残龙凤烛百余条。盖在翰林日，昭宗夜对金銮，宫人秉烛以送。偓悉藏之，识不忘也。偓富才情，词致婉丽，幼喜闺阁诗。后遭国祸，出语依于节义，得诗人之正焉。
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Zephyrca
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保守派们欢迎来美国时政版：
#24 Re: 太空真的是空的嗎
很简单，使用以己度人的原理
及昭宗被轼，携其族往依王审知，终身不食梁䘵。捐馆日，留一箧缄鐍甚密。家人意为珍玩，发之，唯得烧残龙凤烛百余条。盖在翰林日，昭宗夜对金銮，宫人秉烛以送。偓悉藏之，识不忘也。偓富才情，词致婉丽，幼喜闺阁诗。后遭国祸，出语依于节义，得诗人之正焉。
#26 Re: 太空真的是空的嗎
君在杠之头 我在杠之尾 日日杠君不见君 共知杠无悔
及昭宗被轼，携其族往依王审知，终身不食梁䘵。捐馆日，留一箧缄鐍甚密。家人意为珍玩，发之，唯得烧残龙凤烛百余条。盖在翰林日，昭宗夜对金銮，宫人秉烛以送。偓悉藏之，识不忘也。偓富才情，词致婉丽，幼喜闺阁诗。后遭国祸，出语依于节义，得诗人之正焉。
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#31 Re: 太空真的是空的嗎
你一想到什么 原理，就说明你正在应用它
及昭宗被轼，携其族往依王审知，终身不食梁䘵。捐馆日，留一箧缄鐍甚密。家人意为珍玩，发之，唯得烧残龙凤烛百余条。盖在翰林日，昭宗夜对金銮，宫人秉烛以送。偓悉藏之，识不忘也。偓富才情，词致婉丽，幼喜闺阁诗。后遭国祸，出语依于节义，得诗人之正焉。
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#33 Re: 太空真的是空的嗎
宇宙中的真空，就算挤走了所有空气（星际尘埃）等物质，也不是“真”空。a false vacuum. 这种空还是有很高能量的，有种说法一旦发生量子穿隧，产生真的真空，那就会不断向四周坍塌蔓延，宇宙会以光速而完蛋。
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#34 Re: 太空真的是空的嗎
Vacuum decay: the ultimate catastrophe
September 14, 2015
Katie Mack
Katie Mack
Katie Mack is an astrophysicist at North Carolina State University.
Every once in a while, physicists come up with a new way to destroy the Universe. There’s the Big Rip (a rending of spacetime), the Heat Death (expansion to a cold and empty Universe), and the Big Crunch (the reversal of cosmic expansion). My favourite, though, has always been vacuum decay. It’s a quick, clean and efficient way of wiping out the Universe.
140915 mack p
Conceptual illustration of the Higgs Field that physicists believe permeates the Universe, and that could theoretically bring about its end.
Credit: David Parker/Getty Images
To understand vacuum decay, you need to consider the Higgs field that permeates our Universe. Like an electric field, the Higgs field varies in strength, based on its potential. Think of the potential as a track on which a ball is rolling. The higher it is on the track, the more energy the ball has.
The Higgs potential determines whether the Universe is in one of two states: a true vacuum, or a false vacuum. A true vacuum is the stable, lowest-energy state, like sitting still on a valley floor. A false vacuum is like being nestled in a divot in the valley wall – a little push could easily send you tumbling. A universe in a false vacuum state is called “metastable”, because it’s not actively decaying (rolling), but it’s not exactly stable either.
There are two problems with living in a metastable universe. One is that if you create a high enough energy event, you can, in theory, push a tiny region of the universe from the false vacuum into the true vacuum, creating a bubble of true vacuum that will then expand in all directions at the speed of light. Such a bubble would be lethal.
The other problem is that quantum mechanics says that a particle can ‘tunnel’ through a barrier between one region and another, and this also applies to the vacuum state. So a universe that is sitting quite happily in the false vacuum could, via random quantum fluctuations, suddenly find part of itself in the true vacuum, causing disaster.
The possibility of vacuum decay has come up a lot lately because measurements of the mass of the Higgs boson seem to indicate the vacuum is metastable. But there are good reasons to think some new physics will intervene and save the day.
One reason is that the hypothesised inflationary epoch in the early Universe, when the Universe expanded rapidly in the first tiny fraction of a second, probably produced energies high enough to push the vacuum over the edge into the true vacuum. The fact that we’re still here indicates one of three things. Inflation occurred at energies too low to tip us over the edge, inflation did not take place at all, or the Universe is more stable than the calculations suggest.
If the Universe is indeed metastable, then, technically, the transition could occur through quantum processes at any time. But it probably won’t – the lifetime of a metastable universe is predicted to be much longer than the current age of the Universe.
So we don’t need to worry. But what would happen if the vacuum did decay?
The walls of the true vacuum bubble would expand in all directions at the speed of light. You wouldn’t see it coming. The walls can contain a huge amount of energy, so you might be incinerated as the bubble wall ploughed through you. Different vacuum states have different constants of nature, so the basic structure of matter might also be disastrously altered. But it could be even worse: in 1980, theoretical physicists Sidney Coleman and Frank De Luccia calculated for the first time that any bubble of true vacuum would immediately suffer total gravitational collapse.
They say: “This is disheartening. The possibility that we are living in a false vacuum has never been a cheering one to contemplate. Vacuum decay is the ultimate ecological catastrophe; in a new vacuum there are new constants of nature; after vacuum decay, not only is life as we know it impossible, so is chemistry as we know it.
“However, one could always draw stoic comfort from the possibility that perhaps in the course of time the new vacuum would sustain, if not life as we know it, at least some creatures capable of knowing joy. This possibility has now been eliminated.”
To know for sure what would happen inside a bubble of true vacuum, we’d need a theory that describes our larger multiverse, and we don’t have that yet. But suffice it to say, it would not be good. Luckily, we’re probably reasonably safe.
At least for now.
Originally published by Cosmos as Vacuum decay: the ultimate catastrophe
September 14, 2015
Katie Mack
Katie Mack
Katie Mack is an astrophysicist at North Carolina State University.
Every once in a while, physicists come up with a new way to destroy the Universe. There’s the Big Rip (a rending of spacetime), the Heat Death (expansion to a cold and empty Universe), and the Big Crunch (the reversal of cosmic expansion). My favourite, though, has always been vacuum decay. It’s a quick, clean and efficient way of wiping out the Universe.
140915 mack p
Conceptual illustration of the Higgs Field that physicists believe permeates the Universe, and that could theoretically bring about its end.
Credit: David Parker/Getty Images
To understand vacuum decay, you need to consider the Higgs field that permeates our Universe. Like an electric field, the Higgs field varies in strength, based on its potential. Think of the potential as a track on which a ball is rolling. The higher it is on the track, the more energy the ball has.
The Higgs potential determines whether the Universe is in one of two states: a true vacuum, or a false vacuum. A true vacuum is the stable, lowest-energy state, like sitting still on a valley floor. A false vacuum is like being nestled in a divot in the valley wall – a little push could easily send you tumbling. A universe in a false vacuum state is called “metastable”, because it’s not actively decaying (rolling), but it’s not exactly stable either.
There are two problems with living in a metastable universe. One is that if you create a high enough energy event, you can, in theory, push a tiny region of the universe from the false vacuum into the true vacuum, creating a bubble of true vacuum that will then expand in all directions at the speed of light. Such a bubble would be lethal.
The other problem is that quantum mechanics says that a particle can ‘tunnel’ through a barrier between one region and another, and this also applies to the vacuum state. So a universe that is sitting quite happily in the false vacuum could, via random quantum fluctuations, suddenly find part of itself in the true vacuum, causing disaster.
The possibility of vacuum decay has come up a lot lately because measurements of the mass of the Higgs boson seem to indicate the vacuum is metastable. But there are good reasons to think some new physics will intervene and save the day.
One reason is that the hypothesised inflationary epoch in the early Universe, when the Universe expanded rapidly in the first tiny fraction of a second, probably produced energies high enough to push the vacuum over the edge into the true vacuum. The fact that we’re still here indicates one of three things. Inflation occurred at energies too low to tip us over the edge, inflation did not take place at all, or the Universe is more stable than the calculations suggest.
If the Universe is indeed metastable, then, technically, the transition could occur through quantum processes at any time. But it probably won’t – the lifetime of a metastable universe is predicted to be much longer than the current age of the Universe.
So we don’t need to worry. But what would happen if the vacuum did decay?
The walls of the true vacuum bubble would expand in all directions at the speed of light. You wouldn’t see it coming. The walls can contain a huge amount of energy, so you might be incinerated as the bubble wall ploughed through you. Different vacuum states have different constants of nature, so the basic structure of matter might also be disastrously altered. But it could be even worse: in 1980, theoretical physicists Sidney Coleman and Frank De Luccia calculated for the first time that any bubble of true vacuum would immediately suffer total gravitational collapse.
They say: “This is disheartening. The possibility that we are living in a false vacuum has never been a cheering one to contemplate. Vacuum decay is the ultimate ecological catastrophe; in a new vacuum there are new constants of nature; after vacuum decay, not only is life as we know it impossible, so is chemistry as we know it.
“However, one could always draw stoic comfort from the possibility that perhaps in the course of time the new vacuum would sustain, if not life as we know it, at least some creatures capable of knowing joy. This possibility has now been eliminated.”
To know for sure what would happen inside a bubble of true vacuum, we’d need a theory that describes our larger multiverse, and we don’t have that yet. But suffice it to say, it would not be good. Luckily, we’re probably reasonably safe.
At least for now.
Originally published by Cosmos as Vacuum decay: the ultimate catastrophe
#35 Re: 太空真的是空的嗎
不考虑这种情况。宇宙一旦再发生相变，就不是现在这个宇宙了，所有的粒子和力都会消失，新的粒子和作用力会冒出来Highly 写了： 2024年 5月 14日 21:06 宇宙中的真空，就算挤走了所有空气（星际尘埃）等物质，也不是“真”空。a false vacuum. 这种空还是有很高能量的，有种说法一旦发生量子穿隧，产生真的真空，那就会不断向四周坍塌蔓延，宇宙会以光速而完蛋。
及昭宗被轼，携其族往依王审知，终身不食梁䘵。捐馆日，留一箧缄鐍甚密。家人意为珍玩，发之，唯得烧残龙凤烛百余条。盖在翰林日，昭宗夜对金銮，宫人秉烛以送。偓悉藏之，识不忘也。偓富才情，词致婉丽，幼喜闺阁诗。后遭国祸，出语依于节义，得诗人之正焉。
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#39 Re: 太空真的是空的嗎
真空有能量，有正负粒子对
理解了老将是代入狗的视角之后，你就理解了老将
viewtopic.php?t=120513
理解了它们是代入狗的视角之后，它们为什么会嘲笑不愿意当狗的人，以及为什么会害怕想要反抗的人，就都可以理解了：
“放着好好的狗不当”
