In astronomy, few things capture the imagination quite like black holes.
Black holes first entered the scientific world as a concept that was predicted by Einstein's general relativity (which has since become one of the most well-demonstrated concepts in scientific history)--though as far back as the 1700s, people deduced similar concepts from Newton's understanding of gravity. Einstein himself saw the prediction of black holes but thought that they would probably not form in nature. Decades later, Stephen Hawking and Roger Penrose showed the opposite.
Why black holes are black
Imagine that you and your kids hold a blanket and stretch it really tight, so that it is nearly perfectly flat. Now imagine that someone places a bowling ball in the center. The blanket would curve around the bowling ball--and if you were to shoot a marble across the sheet and it got caught in the curve, then the marble would be pulled by the curvature down into the bowling ball.
This is how gravity works: it curves space-time around it, so that if you pass close enough, you fall into the planet at the base of the curved space (which we call a "gravity well.")
Now, imagine that instead of a bowling ball, you put something onto the sheet which is the size of a marble--but weighing a thousand pounds. What would happen? Well, assuming the sheet doesn't rip, it would have an extremely sharp and deep and small curve, wouldn't it? One which, if a marble entered, it could never return--no matter how fast you rolled it.
This is how a black hole works: it warps space-time so dramatically that nothing which enters the curvature (the "event horizon") can ever travel fast enough to leave--even light. Hence the term "black hole"...since not even light can leave it, then we cannot directly verify its existence.
Which of course raises the question--if we can't see the light from a black hole...how can we ever be sure they even exist?
Seeing black holes
Well you can't see a black hole like you could see a star or a gas cloud. And yet...we have pretty strong reason to believe they are real. Why? Because even though we cannot directly see them, we can see things acting in ways that are only explainable if black holes are real. (Remember this...it will be important later.)
- We can see some things which are being bent by gravity...but we cannot see anything in that region of space which could cause such bending.
- If gas was to fall into a black hole, it would form a disc around the black hole and the gas would release potential energy as X-rays...and we have seen exactly these kinds of "X-ray whirlpools" out in space, for which we have no other good explanation.
- We can now observe multiple galaxies near the core, and each one of them shows evidence best explained by a supermassive black hole being at their center.
- X-ray binaries are stars which show evidence of having gas pulled off of it into an accretion disc with nothing in the center--again, strong evidence of a black hole.
|Artist rendition of X-ray binary|
The Christian Connection
Other than the fact that I am a huge astronomy nerd, why am I posting this on my blog? Because I see a strong connection to the Christian life here.
We live in a society which is increasingly skeptical about God. People have (for reasons inexplicable to me) decided that it is preferable to believe we are living in a cold world of meaningless materialism than in a world which--though at times horrible--will one day be redeemed and remade. And so they are skeptical to the extreme about religion.
One of the most common things we hear skeptics say is that they do not want to believe in anything without evidence.
Not a one of those skeptics whom I have met disbelieve in black holes...despite the lack of direct evidence. We do have good evidence of black holes...but the evidence is indirect, not direct. Yet it is overwhelming, and thus widely accepted by normally skeptical people.
So if indirect evidence is good enough for understanding science, surely it too is good enough for understanding spiritual things as well?
No, I do not have any direct evidence that Jesus is real. I did not meet Him. I do not hear Him speak in an audible way. And yet, I would say that I have seen wonderful evidences of Him in my life--indirect, to be sure, but evidences nonetheless.
We live in a world in which even geneticists calculate that random evolution cannot possibly have happened during the lifetime of Earth (more on this in a later post).
We live in a universe in which it is statistically improbable to the extreme to believe that the universe could spontaneously develop to support life as it has.
We live in a world where everyone believes in a shared universal morality, and yet no one lives up to it, and only our faith explains this conflict.
We worship a faith which by no means should have been able to survive, much less become the dominant religion on the planet: it worships a God who was defeated and died, who was shamed as a criminal, and which teaches its followers to accept suffering rather than fight back.
I have seen God at work in my life, in the quiet times and the busy, making me succeed at things well outside of my capability.
I see God doing in my life exactly what He promised to do--changing my heart (often in spite of my desires and prayers!) to make me more loving, peaceful, patient, kind...and I have seen Him do it in countless others.
So have I seen direct evidence of God? No. But I still believe in Him, because even though we cannot directly see Him, we can see events and people acting in ways that are only explainable if God is real.
Just like a black hole, we may not be able to see God, but we can see His massive effect on everything around us and--from this evidence--infer His existence and reality.
To put it in the words of two men much smarter than me:
"Since the creation of the world, God's invisible qualities--His eternal power and divine nature--have been clearly seen, being understood from what was made" (Paul, Romans 1:20).
"I believe in God as I believe the sun has risen: not only because I see it, but because by it I see everything else." (CS Lewis)
Don't buy into the lie that the only allowable evidence is direct evidence. If you look for God's effects--things which are only explainable if He is present--you cannot help but find Him.