Astrophysics of the Interstellar Medium by Walter J. Maciel

The vacuum of space – better than anything scientists can produce in laboratories on Earth – and yet it’s not entirely empty, and has an effect on observations, and that effect can’t be dealt with by just sending telescopes to space.

The idea that there might be something between us and stars isn’t new, but it hasn’t been a long time for us to actually talk about such a field of research as astrophysics of interstellar medium.

In this book one first gets an overview of the history of the field and how we actually know that there is gas and dust in interstellar space – it was one of the reasons why William Herschel’s estimates for the size of our Galaxy were off – as he couldn’t see the dust and it hid the stars behind it.

Although interstellar space is more difficult to observe in some ways than stars or galaxies, modern telescopes can still see a lot of what is going on.

If you have seen some of the images taken by Hubble Space Telescope, you might have happened across colourful images (in fake colours mostly) of nebulae – we might get a glimpse of what there is in addition to stars often thanks to stars illuminating interstellar matter or because of the gas and dust hiding the stars or part of their radiation – certainly many of you would recognize the absorption nebula called the Horsehead nebula in Orion on photo – but how many of us really know what is happening inside and what exactly does the nebula consist of? These are some of the questions you can find answers to in this book, and ofcourse you can get deep into the physical processes that go on in different types of nebulae.

I found this book riveting, as a lot of times in astrophysics we’re dealing with huge objects, and ofcourse interstellar nebulae are huge, but as the book goes down to molecular and atomic scale, we see more of what is happening to individual particles in space. Also after reading this book one can try and imagine all the ways that a photon might interact with interstellar matter. As comparison – when the general public thinks of light coming from the Sun, on would mostly think of it being radiated from it’s visible surface, but we wouldn’t ponder long on how the light and energy get from the Sun’s core out to the chromosphere – same thought pattern would be true for nebulae we might see on pictures. After reading Maciel’s book, you won’t look at nebulae the same way and the vacuum of space will be something extraordinary.

Labels: book review, Walter J. Maciel