Naked Science Forum

Non Life Sciences => Physics, Astronomy & Cosmology => Topic started by: jaiii on 19/01/2014 10:38:50

Title: superconduction
Post by: jaiii on 19/01/2014 10:38:50

Hi.

Whot happend with super conductor when could his les than his criticall themperature?
(temperature of vacuum)

Thank.

By.

Title: Re: supercunduction
Post by: evan_au on 20/01/2014 09:59:08

When the temperature of a superconductor falls below the Critical Temperature Tc (http://en.wikipedia.org/wiki/Superconductor#Superconducting_phase_transition), the resistance suddenly drops to zero. However, superconductivity can be suppressed by the presence of an external magnetic field.

Note that the temperature of an object in a vacuum has no relationship with Tc.
- In the vicinity of the Earth & Moon, the temperature of an object in a vacuum will be about -15C (depending on what container it is in). This is due to the proximity of our Sun, and is far above the Tc for any material we have manufactured*.
- In between galaxies, the temperature of an object in a vacuum will drop down to about the level of the Cosmic Background Radiation, or 2.7K. This is cold enough to turn mercury into a superconductor, but there are other substances with much lower Tc than 2.7K (http://en.wikipedia.org/wiki/List_of_superconductors) 

* It is thought that metallic hydrogen  (http://en.wikipedia.org/wiki/Metallic_hydrogen#Superconductivity) at very high pressures inside Jupiter might be a superconductor at temperatures as high as "room temperature" (25C).
Neutron Stars  (http://en.wikipedia.org/wiki/Magnetars#Origins_of_magnetic_fields) may also be superconducting despite extremely high temperatures