How is the distance to stars measured?

Ever since I started writing about my research period at the Indian Institute of Astrophysics, I have been getting questions about space from many of my readers. So, instead of blabbering on about the proceedings of day 3, I decided to answer one of their questions.

The most common question I got dealt with measurements, a la, just how do we know something is this big, this far, this heavy etc. when we cannot even approach it, let alone handle it, to measure such properties. So I decided to write a brief, mostly qualitative, answer to this question about distances: how exactly do we know how far a certain star or planet is from us? Continue reading

Have we crossed the Great Filter?

One of the biggest arguments regarding the existence of aliens are the famous Drake equation and the equally famous Fermi paradox. I wrote about them four years ago and debated that aliens may still exist in spite of these arguments against them, and I still stand by that belief.

I was reminded of this again recently when I read about a so-called Great Filter theory that attempts to explain the standard sceptic’s question: if aliens exist, where are they? why haven’t we seen or met them yet?

Stemming from astrobiology, the idea behind the great filter is that a civilisation or species reaches a developmental wall it cannot cross. But some — including myself — like to believe that we have already crossed this wall, or filter. And that leads to some interesting ideas. Continue reading

Our Universe: marble or wood?

If there is any fundamental quality of nature that has eluded physicists and sparked debates of a fearful scale, it is the question as to whether the universe has a simple (beautiful) underlying principle that runs quite everything in existence.

Undoubtedly, the dream of every physicist is, as Leonard Lederman creatively summed it up, ‘…to live to see all of physics reduced to a formula so elegant and simple that it will fit easily on the front of a T-shirt.” On a serious note, this highlights the strong belief in most physicists that nature is elegance and simplicity bundled into one.

Physicist Albert Einstein likened this world to marble. In the pith his idea was that the world as we first see it would appear to the observer like wood. Various observations would seem vastly different, unpredictable and complicated. It was his strong belief that we could, on further investigation, chop off these wooden structures to reveal an inside made of marble. Marble he likened to an elegant and simple universe with predictability. Apart from the fact that wood and marble seemed, for some reason, to represent chaos and cosmos to Einstein, it was also an idea that would hold true for almost all discoveries in physics preceding, and including, relativity.

“Maybe nature is fundamentally ugly, chaotic and complicated. But if it’s like that, then I want out.”

—Steven Weinberg


From Newton’s laws to Maxwell’s equations to Einstein’s relativity, with every passing discovery we seemed to have united another chunk of our universe to form a whole; and it was as if we either found new explanations for phenomena or found that new, unexplained phenomena happened to be in coherence with previously explained processes/laws.  Continue reading