Saturday, April 29, 2017

Ingenious Experiments in Astronomy and Physics

This article at space.com describes 5 experiments in astronomy and physics which involve quite a lot of interesting physics...

  • - discovering the first exoplant
  • - measuring the circumference of the Earth
  • - Einstein's thought experiemnts
  • - Millikan's oil drop
  • - Foucault's pendulum


Thursday, March 30, 2017

Some wierd physics

Physicists have developed a new kind of matter which is stable but changes periodically over time. It involves a complex quantum effect and is called a 'time crystal'. According to a report in Physics.org :
"Time crystals may sound like something from science fiction, having more to do with time travel or Dr. Who. These strange materials—in which atoms and molecules are arranged across space and time—are in fact quite real, and are opening up entirely new ways to think about the nature of matter. They also eventually may help protect information in futuristic devices known as quantum computers."
Sondhi said that the work addresses some of the most fundamental questions about the nature of matter. "It was thought that if a system doesn't settle down and come to equilibrium, you couldn't really say that it is in a phase. It is a big deal when you can give a definition of a phase of matter when the matter is not in equilibrium," he said.

Saturday, January 28, 2017

Science podcasts

Some excellent podcasts for science and physics news can be found on the BBC podcast website of which the following I listen to regularly:

The Science Hour - "Science news and highlights of the week"

Science in Action - "The latest science research and news stories from all over the world" There is usually some overlap with "The Science Hour" but still worth getting.

Discovery - "Explorations in the world of science." This usually focuses on one topic.

Space - "Stories, opinion and debate from the final frontier"

and in the IT field there is:

Click - "Technological and digital news from around the world."

Tech Tent - "Your weekly status update on the technology business "

Friday, December 30, 2016

EMDrive being worked on in China

To follow up last month's post it seems that China is pushing forward its research on the EMDrive and may actually be testing it in space already. According to NextBigFuture:
"The China Academy of Space Technology (CAST), a subsidiary of the Chinese Aerospace Science and Technology Corporation (CASC) and the manufacturer of the Dong Fang Hong satellites, has held a press conference in Beijing explaining the importance of the EmDrive research and summarizing what China is doing to move the technology forward.
China Academy of Space Technology (CAST) team statements corresponds with information provided to IB Times from an anonymous source. According to their informant, China already has an EM Drive on board its version of the International Space Station, the space laboratory Tiangong-2."
It seems unlikely that China would invest so much unless they were confident of success.

Meanwhile at NASA the paper referred to last month has been published, confirming a thrust of 1.2mN per kW (report by NextBigFuture).

Monday, November 28, 2016

An exotic space propulsion system

I have not blogged about the EmDrive before although I have followed it for years. It seems far-out - a space propulsion system which is propellantless. It seems to violate the law of momentum. Many still regard it as impossible and there is no generally accepted explanation of how it works. However careful tests, some by NASA, have found that it does seem to produce a small steady thrust.

Remember that effects have many times been pronounced impossible before but later accepted. I am posting an item about the EmDrive as an example of such.

NASA is publishing a paper describing tests they have been conducting, as reported by NextBigFuture.

An article in DigitalTrends gives an overview:
"The issue is, the entire concept of a reactionless drive is inconsistent with Newton’s conservation of momentum, which states that within a closed system, linear and angular momentum remain constant regardless of any changes that take place within said system. More plainly: Unless an outside force is applied, an object will not move."

So how does it work? it uses microwaves - read the article to find out.

Tuesday, October 25, 2016

A nice physics blog

An interesting physics blog by PBS  with links to more physics blogs. According to the blog:
"What is The Nature of Reality? It’s a blog, and it’s pretty much the biggest question we could think of. "
Plenty of videos.

Monday, August 29, 2016

Small floating solar device boils water

An ingenious device using basic physics boils water in sunlight. From an article in Ars Technica:
"Tests in the lab and on the MIT roof showed that, under ambient sunlight, the absorber warmed up to 100 degrees Celsius in about five minutes and started making steam. That’s a first."
A good situation to work out the physics involved and discuss. (Photo - MIT)
Should be possible to make a less efficient copy of this device without the commercial selective absorber coating.