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How would it look like to use a fusion reactor to power a spaceship?
One can read about what a fusion reactor power plant would look like but this amazing technology could power spaceships! We would finally explore our Solar System properly ...
The use of fusion reactions to power spacecraft is still pure speculation but in principle there would be two possibilities. The first option is that the electricity produced by the reactor would be used to operate some revolutionary, not yet discovered type of propulsion ...
Why do we want to try to ignite a completely different type of fusion than the one operated by the Sun?
On the Earth, scientists are trying to ignite a fusion reaction between deuterium and tritium at extremely high temperatures of around 150 million degrees ...
There are many types of fusion reactions that release energy when the nuclei of light atoms fuse. Except for the different temperatures required for their ignition, they have different cross-sections and yields which are parameters that are crucial for the energy use of fusion ...
Will there ever be a wristwatch with a fusion battery?
Nuclear fission reactors are getting smaller. There is talk about small modular reactors, nuclear boilers heating remote villages, small nuclear reactors powering ships and submarines — will the ...
So far, the trend is exactly the opposite, and the new fusion reactors are getting bigger and bigger. It turns out that a larger volume of plasma provides it with better stability and better parameters, thanks to which the fusion reaction can be better achieved ...
Real plasma in flame
Is plasma formed during the burning of a flame? And if so, can the flame react to an electromagnetic field?
Plasma refers to a gas consisting of charged particles. Due to the high temperature of the flame, a neutral gas molecule (e.g., O2) can rupture into a free electron and a positive O2 ion and a candle flame can contain plasma. Indeed, such plasma is very sparse — there are fewer charged particles in it than the recommended molecules ...
The unpredictable path of lightning
Why does lightning sometimes hit a car on the road during thunderstorms, even though there are taller, wet and therefore conductive trees on both sides of the road?
Yes, it can happen, just as it is possible that the lightning does not hit the tree, but rather next to it, or that it does not “choose” the shortest path towards the ground. It is necessary to realize that lightning moves in smaller sections and only when the individual parts of the lightning reach the ground will what we call lightning happen (it is well seen in slow motion videos, e ...
Why is a higher pressure at depth when the water is incompressible?
Water is an incompressible liquid. So how is it possible that there is a high pressure in the sea depths when the water cannot be compressed?
The fact that there is higher pressure in greater depth is not related to compressibility of the fluid but with its weight. Air, unlike water, is compressible and there is also higher pressure at sea level than in the mountains. The air pressure calculation is more complicated than water because for water, we assume that its density is still the same (because it is incompressible) ...
How would the atomic bomb explosion look like in outer space?
In movies, whether we kill aggressive aliens or smash giant asteroids, an explosion in space is always a spectacular affair. What would the explosion of an atomic bomb in a space really look like?
Whether we eliminate aggressive aliens or giant asteroids in movies, an explosion in space is always a spectacular thing. How would the explosion of an atomic bomb in space vacuum really look like?
I am not an expert on nuclear weapons so I apologize in advance for any inaccuracies ...
Is it possible to create two identical snowflakes?
There cannot be two identical snowflakes. But what if two flakes were allowed to crystallize in the laboratory, under exactly the same conditions. Would they be the same or not?
I wouldn’t say two identical snowflakes can’t exist — it’s rather unlikely. There are about 10,000,000,000,000,000,000 ice crystals in a snowflake that randomly coalesce when the snowflake is formed. That’s 100,000 times more than the stars in our galaxy or 10 times more than all people’s hair on our planet ...
How fast is gravity?
If the Sun disappeared out of nowhere, would the Earth leave its orbit sooner, later or at the same time that the Sun would disappear from the sky and darkness would come?
The special theory of relativity shows that it is not possible for any information to spread faster than the speed of light. Thus, the Earth would “learn” of the disappearance of the Sun at the same time that the light from the Sun would stop to fall on it. The speed of gravity spread is the same as the speed of light ...
Why does the pond freeze from the surface?
The warm water rises up, so it should be warmer on the surface of the pond than at the bottom. How is it then possible that a pond always freezes from the surface and not from the bottom?
Yes, that’s right — warmer water rises (that’s why there is, for example, a heating spiral at the bottom of a kettle). In addition, this phenomenon works with all fluids (i.e. liquids and gases) ...
How can a tall spruce pull water from the roots to the top; does it have a pump inside?
A tall giraffe pumps blood into its head by its heart. But what draws water to the top of tens of meters high spruce? Trees have no hearts or pumps…
Capillary elevation is responsible for the nutrition of trees (and other plants)…
You may think that you will not encounter this phenomenon anywhere else but (like all physics) this phenomenon has a wide use. You could ask in the same way why a cloth or a sponge absorbs water.
Liquid molecules (e.g ...
Could bacteria fly?
To move in a water environment, bacteria have various cilia and flagella that they move forward with but in the air, they are passive travellers depending on where the wind blows them ...
I am not a naturalist, so I would rather only physically speculate on this issue. I think it's simple — they don’t need to. Evolutionary theory (in my interpretation) shows that the evolution of animal species prefers those “modifications” of organisms that lead to their better development and survival ...
Can I walk through the wall thanks to the quantum theory?
According to the quantum theory, the position and velocity of any particle is uncertain, so it may happen that the particle just finds itself somewhere other than where it was ...
It’s not that simple — more precisely, the degree of inaccuracy in determining the position and together with speed (momentum) is equal to a very small number (Planck’s constant). If the value of the Planck constant was in the order of hundreds of J ...
Can I make diamonds from coal at home?
Both coal and diamonds are made of carbon, only differently arranged each time. Is there a way in which coal could be turned into a diamond? Can diamonds be “cooked” on a cooker at home?
It is fascinating that the same element (carbon) has diametrically different properties only because of the different composition of the crystal lattice. But because there are the same atoms in coal, a pencil lead or a diamond, people wondered after the discovery of the structure of these substances (late 18th century) if a diamond could not be made artificially ...
Why don’t airplanes flap their wings?
Planes were inspired by birds and all birds flap their wings when they fly. So why don’t planes flap their wings and they are fixed?
I have rather brief information about the history of flying but I think that the inspiration was based on the free flying of birds when they do not flap their wings (e.g. still used today by gliders). The principle of gliding (and therefore the flight of an aircraft) is different from flapping wings. When flapping its wings, a bird rises due to the fact that it bounces off the air ...
Where does all the light go when I turn the lights off?
When I close myself into a room without windows and turn the light on, where does all that light go when I turn it off again? We could ask a similar question with sound (where does sound disappea ...
Like sound or waves in water, light is a wave, only in the case of light, it is an electromagnetic wave while sound is a mechanical wave. So if I describe the waves on the water surface, we can imagine the behavior of light in the same way. Instead of a room without windows, we will describe an arbitrarily large swimming pool with water ...
What is the shape of an electron?
In the schematic diagrams of an atom, electrons are usually painted as coloured balls. But how does an electron really look like?
Unfortunately, I am not a particle physicist, so I hope that I will not be fundamentally wrong in the fact that my answer is: we do not know. More precisely, we do not know and will not know. In our world (in terms of size) we are able to accurately measure, take pictures, and weigh anything. And as our technologies keep improving, we’re able to measure more and more accurately ...
How many bananas can I eat so not to get radiation sickness?
Bananas are said to contain radioactive elements. How many bananas can I eat daily so I don’t get radiation sickness?
Personally, I wouldn’t be afraid that someone could die of a banana overdose. Although the “banana equivalent” is given as an auxiliary unit describing radiation, I do not think that its value reflects the real effect of the banana on the increase in radiation in our body ...
Why is a tidal wave at the opposite side of the Earth than the Moon?
The tide is caused by the Moon attracting the Earth’s oceans. But why is a tidal wave on the opposite side to where the moon is where there should be the least amount of water!
You correctly describe that the tide is caused by the gravitational force of the Moon. The magnitude of the gravitational force depends, among other things, on the distances of the bodies. Therefore, gravity acts the most on the water on the near side of the Earth, and therefore, there is high tide ...
Can astronauts make tea?
In the mountains, the air pressure is lower than at sea level which means that climbers can boil water before it reaches a temperature of 100 °C ...
The effect of atmospheric pressure on the boiling temperature can be imagined as water molecules trying to get out of the liquid. The higher the air pressure, the more air molecules are above the water surface and the more difficult it is for the water molecules to penetrate the air. So if the pressure is zero, water molecules could easily penetrate to the environment ...
