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Is it possible to travel in time?
So far it seems that time travel is limited by causality — this means that the effect can never precede the cause — I can’t be full before I start eating.
Therefore, travelling to the future is real, but it is a one-way journey ...
Is there energy left in the world after a person dies?
In the physical sense, certainly yes, in the philosophical sense, maybe also and whether in the metaphysical sense, I don’t know.
Since we are composed of carbon, oxygen and water, it would be possible to extract these elements from the body and use them, for example, in combustion or nuclear fusion ...
What is a black hole and where does the “suck in” happen?
We all have the experience that when we throw something, it falls to the ground.
The faster we throw an object, the further it lands.
If we throw it very fast, it will not fall to the ground, but will orbit the Earth.
How fast do we have to throw something depends on the mass of the Earth (or the planet we’re throwing on) and the height we’re throwing from ...
What happens to the electricity that people don’t use and the power plant sends to the grid?
Before I get to the answer, I have to remind you that electricity is one of many forms of energy and we “produce” it by converting another form of energy into it.
Typically, we need to move a magnet that rotates between coils (wound wires).
In order to spin the magnet, we can use wind, water, or water vapour obtained by burning different fuels ...
What would happen to our body if we flew at the speed of light?
At first, I have to point out that only light can travel at the speed of light — mainly because it has zero weight.
Anything with non-zero weight would require exactly an infinite amount of energy to accelerate to the speed of light, because at the speed of light the weight of such a body would be infinite.
That is certainly not possible ...
Can a person consciously change their centre of gravity?
In sports, they say “put the centre of gravity in the knees”.
Not only a person can change its centre of gravity but even a cat — to always land on all its legs, it uses its tail among other things.
The position of the centre of gravity depends on the distribution of weight in the body and its shape ...
How was the Universe created?
I’m afraid that with my knowledge I won’t be able to give a perfectly accurate answer and quite possibly no one knows the exact answer.
Actually, no one knows it, because I don’t know that it would be possible to unify the two fundamental theories that describe the origin of the Universe (and of course also the further development, but not in such a close connection) & ...
Is the Universe infinite?
Although this question is not simple, I would rather answer it than what infinity actually is :D Even though we know relatively a lot about the Universe, it is still very little to be able to answer this question unequivocally (of course there are many more questions) ...
Why does the water in a washbasin spin the other way round in the northern and southern hemispheres when you drain it?
We all probably know that a lot of things that are said are not completely true.
And the statement that water in the northern and southern hemispheres always rotates in reverse when it is drained is one of them.
This question is due to the Coriolis force but we can observe its manifestations in other phenomena — e.g ...
Is it possible to measure “telepathic” waves (mind power) outside the body?
For example, affecting another person at a distance greater than 1 m?
We have been able to measure “telepathic” waves for over 150 years — since the first electrodes were attached to the brain and thus since the first electroencephalogram (EEG) ...
What would happen if the Earth stopped rotating?
That would probably be pretty unpleasant, I’m afraid it would almost immediately end all life on the Earth.
The Earth rotates with a frequency of 1 rotation per 24 hours. By a fairly simple calculation, we can find out that at the equator, its speed is over 1,600 km/h (the closer to the poles, the slower the rotation speed) ...
Can anything be faster than light?
It can but it won’t do us any good. I will not deal with hypothetical particles (tachyons), which in my opinion are more of a mathematical game resulting from the Theory of Relativity.
It follows from the Theory of Relativity that when speed increases, the mass of the body also increases. The faster the object moves, the greater is its mass ...
How long can a wind turbine propeller be so that it would not break?
More and more wind farms are being built around the world and they are getting bigger and bigger. Is there a limit to how big they can be? How long can a wind turbine propeller blade be so that it wou ...
The length of the wind turbine’s propeller blades has already exceeded one hundred metres. In 2022, the record was held by a 123 metre long blade from the Chinese firm Lianyungang Zhongfu Lianzhong Composites Group Co., Ltd. (LZ Blades). Even longer rotors can be expected to follow ...
Could nuclear fuel be made from coal or seawater?
Uranium is found elsewhere in the world other than in uranium ore. It is said to be contained in coal or sea water and there is quite a lot of it there ...
Uranium is a heavy element that was created by sequential neutron captures in the cores of massive stars, which then ended their lives as a supernova and scattered most of the elements from their core into the wide space environment, including uranium. Planets eventually formed from this interstellar dust ...
Can a photovoltaic panel produce electricity at night?
A photovoltaic panel generates electricity from the incident light, so in theory it could also generate electricity at night from the light of the stars and the moon. Or from the glow of street lamps ...
A photovoltaic cell produces electricity after the impact of any photon with a suitable wavelength and does not care if it came directly from the sun, bounced off a wall or the moon or flew out of a light bulb. In all cases, the photon induces a photoelectric effect, which leads to a voltage at the output from the photovoltaic cell ...
What lives in the area of a nuclear power plant?
I wonder if there are any animals living in the area of a nuclear power plant and what do they look like ...
The site of a nuclear power plant usually occupies an area of approximately three square kilometres and includes, from the animal’s point of view, a number of attractive biotopes. There are grassy areas for insects and small animals, bushes, roofs, ledges and pipes providing safe shelters and nesting opportunities or open pools under cooling towers for aquatic creatures ...
Why does atmospheric pressure change and how does it affect humans?
Atmospheric pressure varies mainly with weather and also with altitude. Because atmospheric pressure is the pressure caused by the weight of the air column, the higher we are, the smaller the height of the air above us and thus the weight of the air column is smaller and therefore the atmospheric pressure too ...
What is a photovoltaic panel doing with the sun shining on it when no one is drawing electricity from it?
The photoelectric phenomenon inside the photovoltaic panel takes place every time the sun’s rays fall on it ...
A photovoltaic cell is a thin wafer of silicon modified to function as a semiconductor photodiode. When a photon hits its surface, it transfers its energy to one of the electrons, which is released from its electron shell. When enough electrons accumulate, a voltage is generated at the output of the photovoltaic cell ...
How is gravity produced on a spaceship?
Gravity is a property of all material bodies and cannot be directly “produced”. Since the magnitude of the gravitational force depends on the mass and distance of the bodies acting on each other, we can make a smaller model of the Earth with the same gravitational effects on its surface ...
Can water somehow be lost to space, i.e. decrease on the Earth?
It certainly can, and in my opinion, it happens to a very limited extent. If we want anything to leave the Earth’s gravitational field, we have to give it the so-called 2nd escape velocity (or Ve). Everything we throw/fly slower will come back or will orbit the Earth in an ellipse. The value of this speed is (at the Earth’s surface) 11.2 km/s ...
