For all we know it has zero radius: no experiment has demonstrated a finite radius. Mass of electron is 9×10^-31. But it has no size . Because, in the vision of quantum mechanics, electron is considered as a point particle with no volume and its size is also unclear.

The electron is a fundamental particle,it is very small,the second smallest particle after the neutrino. its size interm of a radius is estimated,not measured, about 10^-16 cm., therefore no exact number ,it has rest mass so it occupies certain space size,but this size is too small be measured exactly today.

Diameter, Radius of an Electron

Nobody knows the exact sizes, but a proton has about 1836 times the mass of an electron. The mass of a proton is 1.0073 u, and the mass of an electron is 5.486×10-5u . Therefore, a proton has about 1836 times the mass of an electron.

Because an electron is a quantum object with wave-like properties, it must always be vibrating at some frequency. Furthermore, an electron in a stable atomic state does not move in the sense of waving through space. The orbital electron does move in the sense of vibrating in time.

Light has no mass so it also has no energy according to Einstein, but how can sunlight warm the earth without energy? Light indeed carries energy via its momentum despite having no mass.

Light has energy, energy is equivalent to mass, and mass exerts gravitational force. Thus, light creates gravity, i.e. the bending of space-time. Thus, in order for light to generate a gravitational field like that of the Earth, it would need to have the mass (energy) of the Earth.

Einstein’s work taught us many things: that space and time are connected, that you can never travel faster than light, that our universe has a finite age and that different observers experience different lengths of time.

Well, not for light. In fact, photons don’t experience any time at all. From the perspective of a photon, there is no such thing as time. It’s emitted, and might exist for hundreds of trillions of years, but for the photon, there’s zero time elapsed between when it’s emitted and when it’s absorbed again.

The speed of light (3×10^5 km/ second) is way faster than the speed at which the electrical signals in our brain propagate (~500km/ hour). Naturally, the thought process of the brain also takes place at the same pace. Hence, light always wins the race.

Q: Which object travels faster than light? The controversial hypothetical particles Tachyons are said to travel faster than light. However, according to Einstein’s special theory of relativity particles regarding speed of light, they can never travel faster than light in the real world.

There Are at Least 4 Ways a Black Hole Could Kill You

• Spaghettification. Black holes form when a massive object, like a star, collapses and squeezes all of its mass into an impossibly small point with infinite density, known as a singularity.
• Fried by Accretion Disk.
• Zapped by Plasma Jet.
• Incinerated by Firewall.

Scientists have therefore started creating artificial black holes inside labs to study their properties. And one such experiment, carried out by scientists at the Technion- Israel Institute of Technology, has proved that Stephen Hawking had been right about black holes all along.

The simple answer is, “Yes, it is possible to stop time. All you need to do is travel at light speed.” We know that an object, or a light beam’s, speed measures the distance traversed over time.

There is no way a black hole would eat an entire galaxy. The gravitational reach of supermassive black holes contained in the middle of galaxies is large, but not nearly large enough for eating the whole galaxy.