Blog Post 2: Hope in the form of Primordials

Welcome back everyone,

Without further ado, let’s get right into the midst of my research regarding black holes.

It is very important to note that contrary to popular belief an incredibly large amount of mass, is not a necessity for a black hole. In reality, what defines a black hole is its density, or rather infinite density – the singularity. The mass of the singularity creates the Schwarzschild radius, which in turn creates the event horizon. So there is a potential that there could be micro black holes. In fact, if your body was compressed into an infinitely small area you could become a black hole with Schwarzschild radius a few picometers (10 ^ -12 meters) across. Thus, the defining characteristic of a black hole is not its mass, but its density.

One way to prove that something has a large density (we cannot reach infinite density without specialized equipment) is to show the mass of an object remaining constant as its volume shrinks. We decided to do just that by taking a balloon, wrapping it with tin foil, and then decreasing its volume by poking a hole in it and slowly compressing it. This experiment successfully showed how a black hole retains its mass at various different sizes, which would eventually lead to infinite density.

Mass is still a property of a black hole. Black holes have three properties – its mass, its speed of spinning and its electrical charge. They are divided into categories along these lines.

Black holes that are created when large stars collapse on themselves are known as Schwarzschild black holes or Newmann black holes depending on whether or not they rotate or have charge. Both of these black holes have masses that range from a couple of time the Sun’s mass to several billion times the mass of the sun. Now when it comes to harvesting black holes, the selection of the correct type of black hole is crucial. And unfortunately, the chance of harvesting these types of black holes (Schwarzschild or Newmann) is slim.

However, in recent years astrophysicists have discovered a new type of black hole, it’s called the primordial black hole and is much much smaller than the earlier stated two types. Most of the primordial black holes were created during the big bang due to high concentration of mass in a small area of space. These black holes can be so small in fact, that it is theorized that particle accelerators could one day create them here on Earth!

When black holes give off Hawking radiation, they are actually giving up mass as well, because E = mc^2 means that as you lose energy you lose mass as well. This means that black holes convert mass into energy at different rates. Research shows that smaller black holes convert mass into energy at quicker rates. This also means that larger black holes emit radiation at a much slower rate. This is the reason the Schwarschild and Newmann black holes are unusable for energy generation.

Knowing that this sweet spot is much smaller than the massive star-collapsed black holes means that one day we could artificially make black holes by concentrating energy in one location. For example, through a spherical gamma-ray laser we could focus the energy into creating a black hole. Also, because these types of black holes are much smaller, we could use them for things like propelling star ships at near-light speed and furthering interstellar travel to the edges of the galaxy. The possibilities are endless!

Here is a great video to enjoy before we part:

Well folks, until next time!

Dr. Chinmay Patel (PhD in Astrophysics)

Professor at Stanford University

Links:

Ball, Philip (Dec 3, 2013). Could we harness energy from black holes? Retrieved From: <http://www.bbc.com/future/story/20131203-could-black-holes-provide-energy>

Anderson, Ryan (November 19, 2009). Black Hole Drive could power future Starships. Retrieved From: <http://www.universetoday.com/45571/black-hole-drive-could-power-future-starships/>

Jones, Zimmerman, Andrew (2010). What is Hawking Radiation? Retrieved From: < http://physics.about.com/od/astronomy/f/hawkrad.htm>

123HelpMe.com. "Black Holes: The Power Source for Future Space Travel?" Retrieved From: <http://www.123helpme.com/view.asp?id=43865>

Whiting, Jim. (2011). Mysteries of the universe: Black Holes. New York, USA. Publisher: Creative Education. Book.

DeGrasse, Tyson. (2007). Galactic Engines. Death by Black Hole and Other Cosmic Quandaries. (pg. 268-274). New York, USA. Publisher: Norton. Book.

Begelman, Mitchell. (2010). Gravity Triumphant. Gravity’s Fatal Attraction: Black Holes in the Universe. (pg. 1-22). New York, USA. Publisher: Cambridge University Press. Book.

#Chinmay