The beat that Earth's heart skipped

• Autores: Mark Viney
• Localización: New scientist, ISSN 0262-4079, Nº. 2925, 2013, pág. 10
• Idioma: inglés
• Texto completo no disponible (Saber más ...)
• Resumen

  • Three times in the last decade Earth's spin has missed a beat. These seemingly random blips cause days to temporarily stretch and shrink. They have emerged from the clearest ever view of how long a day is. Richard Holme of the University of Liverpool, UK, looked at 50 years of GPS and astronomical data to see how day length varied during that time. The analysis threw up a well-known cycle due to slow changes at the Earth's core, which lengthen days by a few milliseconds over roughly a decade, then shrink them down again. There's also a 5.9-year cycle, due to a persistent wobble between the fluid outer core and surrounding mantle, which changes day length by fractions of milliseconds a year.