Liquefaction of solid bulk cargo

This article from The Conversation on problems caused by unexpected behaviour of granular materials  in a ship’s hold has some interesting physics behind it.

"Solid bulk cargoes – defined as granular materials loaded directly into a ship’s hold – can suddenly turn from a solid state into a liquid state, a process known as liquefaction. And this can be disastrous for any ship carrying them – and their crew." 

Ice on the Moon

India's moon orbiter Chandrayaan-1 has detected clear signals of water ice on the Moon hidden in dark corners of craters never reached by sunlight.

From this BBC report:

"Temperatures on the Moon can reach a searing 100C in daytime, which doesn't provide the best conditions for the survival of surface ice.
But because the Moon is tilted on its axis by about 1.54 degrees, there are places at the lunar poles that never see daylight.
Scientists estimate that temperatures in permanently shadowed craters at the Moon's poles do not rise above -157C (-250F). This would create an environment where deposits of water-ice could remain stable for long periods."

Is this a physics story? It does contain some good physics. And I don't always come across a great physics story every month so it will suffice. I like to keep up this blog even though it has been a few years since I have taught physics! Month-end approaches and time is running out...

More podcasts

The Physics World Science Podcast is a good weekly podcast from Physics World magazine.

Weekly Space Hangout Audio is also good for up-to-date space news.

And finally there is the more advanced Physics Frontiers podcast for those really into Physics at the university or post-grad level.

Water is more than you think it is

Water molecules actually exist in two forms: ortho-water and para-water. This is not a new discovery but we now know more about these forms. An article at Science Daily explains:

Water molecules exist in two different forms with almost identical physical properties. For the first time, researchers have succeeded in separating the two forms to show that they can exhibit different chemical reactivities.

The article describes new details about the small differences in the chemical properties of these forms.

Amateur Astronomy Association of Guyana

This local group has recently become active complete with website and Facebook page. According to the website:

"AAAG has a wide range of planned activities: from camping trips under a dark sky retelling the story of our current scientific understanding of the universe, to guided night sky tours of celestial objects, and future events featuring education workshops and lectures in astronomy; we will offer a bit of everything for everyone."

Some good science podcasts

Here are a few I have listened to regularly for the past few years:

Science Hour (BBC) - "Science news and highlights of the week" - a weekly report of five or so good science stories.

Science in Action (BBC) - "...brings you all the week's science news" - shorter than the above, some overlap but good additional stories.

and a more recent find:

Astronomy Cast - More technical than those above, each episode has a theme. Good science plus astronomy updates.

These can easily be found using standard podcast apps.

Another star passes close to our solar system

Apparently some 70,000 years ago a small red star called Scholz's star passed close to our solar system. According to a report at Space.com:

 "... a red dwarf called Scholz's star apparently grazed the solar system 70,000 years ago, coming closer than 1 light-year to the sun.
...Scholz's star passed by the solar system at a time when early humans and Neanderthals shared the Earth. The star likely appeared as a faint reddish light to anyone looking up at the time..."

The research involved studying the orbits of objects on the edges of our solar system and working out how these orbits changed over the ages.