The Universe Revealed

Is space empty?

Is space empty?

I thought that it would be a good time to settle this question. Outer space is the void that exits beyond our planet's atmosphere. The big question is whether it's actually empty.

First, one must define what empty is: empty would mean there is absolutely nothing. Is this what space is?

The answer is resounding No! The list of stuff that is in space is interesting: Low density particles; hydrogen and helium plasmas; electromagnetic radiation; magnetic fields; neutrinos, cosmic rays and even dust. That doesn't sound empty to me.

Space isn't even at absolute zero. It has a base temperature of 2.7 Kelvin degrees (-454.81 degrees F). There is at least one hydrogen atom per cubic meter. There are also other things that we don't really understand, like dark matter and dark energy. Dark energy pervades the entire universe.

Space is considered in most cases to be a hard vacuum. A perfect vacuum is very difficult to achieve. In fact, a perfect vacuum is one of the holy grails of science. A high quality vacuum would consist of 10 to the -12 power atmospheres and 100 particles per cubic centimeter. Outer space is a better vacuum than that, about 4 particles per cubic meter. However, space is not a perfect vacuum.

The other problem with space is that Einstein showed that it is not empty but is in fact a matrix of sorts, a fabric that can be stretched and compressed. You couldn't do that to a perfect vacuum.

This goes back to my discussion about 'Can there be nothing' in my book 'The Theory of Nothing'. The answer is: 'nothing' is impossible in our universe. In other words, there is always something, and that applies to space.

Space is a dangerous and violent media to transverse. This is something that astronauts will have to deal with on a trip to Mars. There are lots of tiny asteroids and space dust beyond Earth, and a spacecraft must deal with providing shielding against collision with these objects. At the speed that a spacecraft must achieve to leave Earth, a collision could be fatal. One way to deal with this is to surround the ship with a magnetic field. Many particles in space are charged and a magnetic field would deflect them. Another scheme is to surround the ship with a hot plasma field. This would vaporize many smaller objects. The only other idea would be to cover the ship with a hard shell of some exotic material that would take a hit without serious damage.

Larger asteroids could be avoided with a slight course change or be destroyed with a powerful laser. But, this isn't the only danger to worry about. Radiation could be very intense in space. One needs a shield to deflect radiation. A magnetic shield would help and some have suggested filling the outer walls of the ship with water. As it turns out, astronauts receive a larger dose of radiation in space than we do on Earth. Long exposure could result in cancers or systemic and genetic damage.

The main thing to remember is that space is not empty or a perfect vacuum. It's filled with bad things, things that are lethal to humans. We were not created to go into space so we need technology to protect us in this hostile environment.

Thanks for reading.