Earth days are shorter than 5 minutes

A new method of measuring the rotational speed of large gas planets shows that Saturn's days are 10 hours, 34 minutes and 13 seconds - 5 minutes shorter than previous calculations based on the planet's magnetic field.

The study, published in the July 30 issue of Nature, is conducted by an international team led by scientists from Oxford University and Louisville University (USA).

Measuring the rotation of a giant gas planet like Saturn is difficult because the planet has no solid surface to use as a benchmark. Simultaneously unlike Saturn, Saturn's magnetic field is in the same direction as its rotation axis so that the oscillation of the magnetic field does not give an accurate measurement of the rotation of the deep inner part of the planet.

The new method began to be used more than 10 years ago by Timothy Dowling of Louisville University when measuring the movement of ammonia clouds on the surface of Saturn and in research by Professor Peter Read of Oxford University, who used data from infrared spectroscopy of NASA's Cassini spacecraft to study the planet's atmosphere since 2004.

A new method of measuring the rotational speed of large gas planets shows that Saturn's days are 10 hours, 34 minutes and 13 seconds - 5 minutes shorter than previous calculations based on the planet's magnetic field. (Photo: NASA)

Professor Peter Read of the University of Oxford's School of Physics, author of the paper, said: 'We realized that we could combine information about what is visible on Saturn's surface. with Cassini's infrared data about the inner depth of the planet to build the first three-dimensional space of wind on Saturn. With this map we can track how large waves and whirlpools form in the atmosphere and from there can measure the planet's rotation. '

Dr. Read said: 'It seems the fact that the day on Saturn is less than 5 minutes is nothing significant, but it shows some previous measurements of wind speed that can deviate up to 160 miles per hour. ! It also means that the weather cycle on Saturn is almost the same as what we observed on Jupiter, showing that, despite differences, the two planets have more in common than we thought. '

The new finding may be crucial in understanding the deep inner part of the planet whose rotation is more complex than a solid object because it is formed from liquid gas.This finding also provides clues about the evolution of Saturn and other giant planets - such as Jupiter, Uranus and Neptune.

Refer:
1. PL Read, TE Dowling & G. Schubert.Saturn thời gian thời gian từ của cơ sở dữ liệu planetary-wave configuration.Nature, 2009;DOI: 10.1038 / nature08194