TIDK #2 – My gravitational radius

One thing I learned pretty quickly was that astronomers don’t only use a lot of weird units (like milliCrabs for example – more on this in another post) but they also use a lot of terms that don’t mean much at first hearing by the unenlightened.  One such is ‘gravitational radius’… someone may say that something is ‘three gravitational radii from” an object. Continue reading “TIDK #2 – My gravitational radius”

TIDK #1 – Neutron star interiors

TIDK = Things I Didn’t Know… until I started gathering the knowledge that in another lifetime may have made me a professional astronomer. This may become a long list…

I knew that neutron stars were stellar remnants, leftovers of stars that had finished with nuclear fusion and collapsed under their own gravity to the point where protons and electrons were crushed together to create more neutrons to join those that were there already.  So my answer would have been “neutrons” whether you had asked me “what’s the surface made of?” or “what’s the centre made of?”. Neutrons all the way down and through. Continue reading “TIDK #1 – Neutron star interiors”

Free text books

If you have an institutional sign-in to Springer Nature then you have the opportunity to download free soft copies of hundreds of text books.  Springer Nature has taken this admirable initiative in support of worldwide learning and teaching institutions which are currently closed because of the Corona virus pandemic.

Simply click on this link and then download an Excel spreadsheet giving details of all the books on offer, including a download URL for each one. Continue reading “Free text books”