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General Discussion & Feedback => Radio Show & Podcast Feedback => Topic started by: thedoc on 16/10/2012 12:05:46

Title: Discuss: Sensors and Sensibility
Post by: thedoc on 16/10/2012 12:05:46

Smart sensors can open a window into the environment.  In this week's Naked Scientists Podcast we find out how networks of sensors around Heathrow airport can study how planes alter the atmosphere, and how a similar network can monitor an Oxfordshire floodplain.  Plus, we find out how the tools of a surgeon are helping to keep jet engines in flying form.  In the news, we hear how gut bugs promote blood vessel growth, why fresh fruit and veg gives you a healthy hue and how scientists are analysing antimatter with microwaves...
Listen to this Show (http://www.thenakedscientists.com/HTML/podcasts/show/20120311/)

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Title: Re: Discuss: Sensors and Sensibility
Post by: algatto on 14/03/2012 22:24:48

My question follows on from the story in the last podcast about observing antimatter.
How do we know that all the galaxies we see in the universe are made of matter and that some of them are not made of antimatter? Is the light generated by antimatter stars different to that generated from stars made of the same matter found in our galaxy? Gravitational effects are expected to be the same. So how do we know that there is an imbalance of antimatter and matter in the observable universe?

Title: Re: Discuss: Sensors and Sensibility
Post by: evan_au on 11/06/2012 10:16:42

We know there is a matter/antimatter imbalance/asymmetry in our part of the galaxy.
If there were a matter/antimatter mixture in our galaxy, we would expect to see gamma rays from matter/antimatter annihilation until only one type is left; we don't see this, so we assume that the same imbalance exists throughout our galaxy.
If different galaxies or galaxy clusters were matter and antimatter, we would expect to see some X-Rays/gamma rays from matter/antimatter annihilation on the border of these zones. This is the subject of a current search:  http://en.wikipedia.org/wiki/Antimatter#Origin_and_asymmetry
The reason for the matter/antimatter asymmetry is still unclear, but some nuclear reactions are known which have a slight matter/antimatter imbalance.