This is an awesome book on Black Holes. And about one of the greatest intellectual wars in the recent times. Though the core theme of the book is the information paradox pertaining to the Black Hole physics, the book covers the fundamentals of some of the fundamental sciences (esp. Quantum Mechanics, QCD, String Theory) that lead to a better understanding of what happens in and around black holes. There a good deal of explanation around what ‘Information’ is. I had heard Leonard Susskind on a few popular science documentaries. Not everyone can explain things well. But Susskind can. The book also led me to some interesting (and disturbing) stuff that we were never taught. Like, energy may not be conserved in general relativity!!!! We’ll, it is not that simple, but then, no one really understands 🙂
There have been some very recent developments around the Black Holes. So better read this book before the information becomes obsolete!
- When you look at the moon, you are looking a little more than a second into the past.
- When you look at the sun, you are looking a little more than 8 minutes into the past.
- When you look at the pole star, you are looking about 430 years into the past.
- The list goes on. There are stars, galaxies, galaxy clusters which could be your window to the past ranging from a few years to billions of years!
You could actually go on into the past until about a few hundred million years after the Big Bang (I wouldn’t get into the technicalities of why we can’t see beyond). We don’t even know if some of these exist as of today when we are looking at them.
With naked eyes you can only see up to a certain limit. Telescopes can push you into the realms ranging from a few seconds to a few billion years into the past. I always wanted to push beyond what I could see with naked eyes. I started with a pair of astronomical binoculars. Little did I know that just a small magnification can help you improve the visibility into the past drastically.
I wanted to push this further. And luckily I got this opportunity a few weeks ago. I came across a large enough telescope and a very knowledgeable and generous guide, Kiran. When you look through a telescope, you don’t get to see the planets, stars and galaxies like those glossy high resolution images. You need to use your imagination to understand what you see.
When I first saw Saturn with its rings clearly demarcated, I somehow felt a personal connect. There was a feeling of possessiveness. After all I was not looking at an image. I was directly looking through the air. The galaxies looked like sugar sprinkled on paper. A few galaxy clusters again looked like salt sprinkled on paper. And when I paid a little more attention, I could make out that they were concentrated towards the center. I thought, could there be a black hole at the center? To my delight, Kiran confirmed that there is a black hole at the center indeed! It was like attaining nirvana! Can you imagine? I was staring at a black hole. Wow!
And it was not over yet. It turned out to be a lucky night for stargazing. The lazy city of Mysore provided an amazing backdrop for an exciting starry night. I saw a white dwarf! Yes, a dying star!! It had exhausted its fuel and had blown into a giant white shell, with a black dot, which was the core.
I stopped for a moment to think that I am looking at something which happened millions of years ago. When humans still hadn’t evolved. Probably when dinosaurs walked the Earth. Or maybe beyond that. I wanted to push back further. But alas! You can’t get into the billions. You probably need to get over the Earth’s atmosphere to look back to that scale. That is what the Hubble has been doing.
But I was more than satisfied with what I saw. I saw the child inside me waking up. I would never forget that night.
Some day, I wish to push the limits and get closer to the big bang by looking through one of the giant telescope arrays.
The reason I am compelled to write this post is that I’ve just got a payment reminder for the domain. I must write something, else I’ll not feel good while releasing the payment. Thanks to Ankit, I haven’t yet paid anything for hosting.
I didn’t know what to write about. So I will just mention a few pointers on faster than light travel which I have come across recently. We all know that Einstein’s relativity puts a limit on the maximum speed through which anything can travel; and the limit is the speed of light, which is constant.
I read an interesting interpretation somewhere. One can’t ‘encounter’ something which travels faster than light. To understand what it means, imagine that two of us stand 1 feet apart. And suddenly, the space between us rips apart at speeds faster than the speed of light. So we may be moving away from each other at faster than light speeds, but we wouldn’t ‘encounter’ it. We would never be able to see each other until the space keeps expanding at those rates. But hold on! If such a thing does happen and suddenly someone disappears from our sight, wouldn’t that itself prove that faster than light travel is possible? By not ‘encountering’ each other, wouldn’t we actually ‘encounter’ faster than light travel?
Wow! I just did a thought experiment like Einstein! And also found a paradox. Not bad. And that too triggered by a $10 domain renewal bill. Innovation can’t be this cheap. Something must be wrong. Find out 🙂
No matter how hard I think, I can’t even come close to visualizing space time. And I am sure not even Einstein could , though he was the one who came up with the counter-intuitive and bold concept of time dilation. While the maths is absolutely spot-on and it has lived up almost a century now, describing the world at an macro scale scale (yes, the quantum world has got a different set of maths), I am sure it would take us ages to be able to engulf it (but if Darwin was correct, we would ultimately “evolve” to be able to visualize it, provided we survive long enough).
Anyways, to cut it down, I somewhere read that the diameter of the observable universe is about 97 billion light years, i.e. it is about 48.5 billion light years radially. How can that be? If nothing can travel faster than light, and the age of the universe is about 13.7 billion years (that is when the big bang happened) how could there be anything visible beyond 13.7 billion light years? This question (and a 100s of others) pop-up every now and then to me. I am lazy enough to sit on them for quite some time until it starts disturbing me. And this one did! And it took just about 10 minutes to get the answer (or rather explanation). So the idea is that the space itself can expand. I knew space could bend, but now I know it can expand as well. Well, even if the space expanded at the speed of light, the radius of the universe should have been about 27.4 billion light years. But that is not the case. The answer to this is that space did not respect Albert Einstein and it decided to expand faster than the speed of light! Wow, isn’t that really cool? With this, even if someone says that the universe is a billion billion quadrillion light years in the diameter, you can’t question that, could you? I noticed that there is already the notion of *observable* universe. There are things beyond that, which we can’t see.
Could the mysterious and illusive dark matter, which is yet to be understood throw some light on it? To me space itself is nothingness (though it can be filled with something), and how could nothingness expand? What if the dark matter (or something else) is such that it makes light travel ridiculously slow when it passes through it? Wouldn’t it make all our distance observations overestimated? Well I know, there are enough reasons for this not being true, else someone would have brought it up for sure. But the point is that it looks to me, that in the last century or so we have created a complicated aura around all this. It has to be simpler. It really has to be. Otherwise it is not true.
Cosmology has always attracted and eluded me since childhood. I just wish that during my lifetime, we witness a spectacular theory or discovery which takes us a step ahead. Wouldn’t it be cool if we discover the mysterious dark matter? Or the fact that things can travel faster than light? Or something more beautiful than E=Mc2
And then, there’s quantum mechanics. I wouldn’t talk about it in this post at all. Einstein wouldn’t have liked it 🙂