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Skywatching

Kicking up a lot of cosmic dust

Dust in space

By now most of us must have seen the incredible images produced by the James Webb Space Telescope.

Then of course, there are the beautiful images obtained using the Hubble Space Telescope. The images obtained using ground-based telescopes, such as the Canada France Hawaii Telescope are pretty stunning too. The interesting thing is that the stuff that makes those images so spectacular is dust and gas. Without it the images would "just" show lots of stars.

The clouds are being hit by equivalents of the solar wind given off by stars. In other places they are being blasted by the explosions of dying giant stars. All this, together with the flows and eddying of the clouds as they move through space, produces all sorts of structures, including rings, shells, blobs and towers.

These are lit up by stars. In addition, ultraviolet light from those stars makes the gases in the clouds fluoresce, glowing red, pink and other colours. The result is those amazing images our telescopes are giving us.

However, in many ways, some of the most exciting stuff is happening in the dark, cold clouds, which we only see with our radio telescopes, or where they lie against a bright background of glowing gas. It is in those clouds that we believe the ingredients for life are produced. In many ways those clouds are like the soil in our fields and gardens. Billions of years ago, the soil was just pulverised rock, like the soil (also called regolith) on the Moon.

Then the first, primitive plants appeared, obtained nourishment by breaking down the rock minerals, and when they died, added their organic remains. So today, our soil is made up of rock minerals and material from generations of plants. It is the reservoir to which materials return and where new life obtains its nourishment.

The cosmic dust and gas clouds are the universe's soil. In the beginning it was just hydrogen and helium. Waste materials from dying stars added all the known elements. Over eons, in the cores of cold, dark clouds, these elements combine to form a witches' brew of chemicals.

These chemicals have signatures we can detect with our radio telescopes, so we know something about the chemical reactions going on. The problem is not in detecting chemicals. The problem is that there are so many chemicals, and so many signatures, it can be a challenge to identify them.

When we put a mixture of the most common cosmic chemicals together in the lab, and hit the mixture with ultraviolet light or electrical discharges, we get a dark gunk that contains amino acids. These are the building blocks of proteins, which are fundamental to life as we know it.

Radio telescopes have detected simple amino acids in those dark, cosmic clouds. The idea that the seeds of life arrive on a new world from out there in space has been around for decades. It is called "panspermia". When planets form from cosmic gas and dust, they get a ration of amino acids and other organic chemicals that could form the foundation for the appearance of life.

However, although it is true that aminoacids are the building blocks of proteins, one protein molecule can contain up to thousands of amino acid molecules. What can make cosmic amino acid molecules combine in large numbers in a precise way is not yet understood.

A pile of bricks very rarely turns into a building all by itself. Maybe the precise conditions on the young planet determine whether this assembly happens and gets what we would call life started. This step probably dictates how widespread life is in the universe. We can be sure that, even sharing their chemical origins, those aliens won't look like us.

•••

Mercury, the closest planet to the Sun lies low in the sunset glow. Venus, the next planet out, shines brightly above it, and Mars, planet 4, is still high in the south. The Moon will be Full on the 5th

Ken Tapping is an astronomer with the National Research Council's Dominion Radio Astrophysical Observatory near Penticton.

This article is written by or on behalf of an outsourced columnist and does not necessarily reflect the views of Castanet.



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About the Author

Ken Tapping is an astronomer born in the U.K. He has been with the National Research Council since 1975 and moved to the Okanagan in 1990.  

He plays guitar with a couple of local jazz bands and has written weekly astronomy articles since 1992. 

Tapping has a doctorate from the University of Utrecht in The Netherlands.

[email protected]



The views expressed are strictly those of the author and not necessarily those of Castanet. Castanet does not warrant the contents.

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