Ask Ethan: Can A Laser Really Rip Apart Empty Space?
“Science Magazine recently reported that Chinese physicists will start building a 100-petawatt(!!!) laser this year. Can you please explain how they plan to achieve this, and what unique phenomenon this will help physicists explore? Such as, what exactly is “breaking the vacuum?"”
As we strive for the greatest frontiers in physics, that always means pushing the limits. To that extra digit closer to absolute zero, the extra factor in high energy particles, the extra depth into the distant Universe. Or, in the case of laser physics, to that extra intensity: power focused into an extremely narrow space. There are three things you need to up that to the maximum amount possible:
-the most extreme amount of energy, -in the shortest-span of a pulse, -focused on the narrowest area possible.
If you can make it all the way up to a high enough energy, you should be able to rip electron/positron pairs out of the quantum vacuum (empty space) itself. Colloquially, people have started calling this “breaking the quantum vacuum,” but in reality, nothing gets broken.
“On Earth, we’re currently burning more than ten billion tonnes of fossil fuels per year worldwide, supplying some 80% of our energy needs through those methods. Unfortunately, air-and-water pollution, along with vast atmospheric changes, have arisen from this. Renewable sources of energy are one potential (although, arguably only a partial) solution, but nuclear power — if it can be done safely — could solve our fossil fuel problem today, with current technology alone. With the amount of fuel it presently takes to power the world, the cost of doing nothing is not only far too high, but will be borne by humanity for generations to come.”
Arguably the greatest advance of humanity
and the cause of the greatest increase in our quality of life — in the past few centuries has been the widespread availability of electrical energy. It powers our homes, our industries, our automobiles, our places of business and more. Our world runs on energy, with the world using upwards of 155,000 TeraWatt-hours annually. That’s a huge amount of energy, and it requires a huge amount of fuel. But must it? If we were to power the world entirely with coal, oil, or natural gas, it would take billions of tonnes of fuel each year to make it happen. If we switched to nuclear, those “billions” drop to thousands. And if we could switch to nuclear fusion or even antimatter, the amount of fuel plummets even further. Looking at the numbers, it makes no sense not to switch. Is it only our fears of nuclear disaster that prevents us from using our current technology to better the world for humanity for generations to come?
Ask Ethan: Could We Save The Earth By Migrating It Away From The Sun?
“I want to dream a bit: do you think it could be physically feasible to migrate the earth’s orbit with our current knowledge in science?”
Someday, in the far distant future, the evolution of the Sun will cause it to heat up and emit so much energy that the Earth’s surface will reach a terrible threshold: 100 degrees Celsius (212 degrees Fahrenheit). When this happens, the oceans will boil away, rendering the surface completely uninhabitable and inhospitable to even the most extreme known forms of life. While there are many potential solutions, perhaps the most intriguing is to migrate the entire planet farther away, buying our world additional billions of years of potential habitability. However, the energy costs are huge, and the amount of power required is much larger than anything humanity has ever known. Is it physically possible? Yes. But from a practical perspective? There are, shall we say, challenges.
There are a couple of times especially in engineering where it is easier to think of DC electric circuits in terms of hydraulic circuits and vice versa. And I think in this case it might help you as well.
Current: The amount of water flowing through a section of a pipe over time
Voltage: The difference in pressure between two points in the water circuit.
Resistance: Narrow constrictions offer high resistance and every pipe like every other wire offers resistance to the flow of water.
Power: It is the rate at which the energy stored in the water is used to drive a mechanical device like a water wheel.
Think of it like this: How fast the wheel is going to spin is dependent on the amount of water hitting it (current) and how much pushing this quantity of water does (voltage).
(pressure = force applied / area)
Hope this helps and I am glad that you are finding the blog to be useful. Cheers!