February 21st, 2013 by James Ayre
An enormous sunspot, six times larger than the Earth is currently forming on the Sun. NASA researchers predict that the sunspot could begin triggering powerful solar flares in a couple of days.
The enormous sunspot has been monitored by NASA’s Solar Dynamics Observatory over the last 48 hours as it has developed. SDO is permanently monitoring the Sun, one of a few spacecraft that does so.
“It has grown to over six Earth diameters across, but its full extent is hard to judge since the spot lies on a sphere, not a flat disk,” said NASA spokeswoman Karen Fox, of the agency’s Goddard Space Flight Center in Greenbelt, Md.
The region where the sunspot is located “is actually a collection of dark blemishes on the surface of the sun that evolved rapidly over the last two days. Sunspots form from shifting magnetic fields at the sun’s surface, and are actually cooler than their surrounding solar material.”
Many of the most intense magnetic fields in the sunspot are currently pointing in opposing directions, which means that solar flares and CMEs are likely in the near future.
“This is a fairly unstable configuration that scientists know can lead to eruptions of radiation on the sun called solar flares,” Fox elaborated.
“The sun is currently in the midst of an active phase of its 11-year solar weather cycle and is expected to reach peak activity sometime this year. The current sun weather cycle is known as Solar Cycle 24.”
Launched very recently in 2010, NASA’s Solar Dynamics Observatory was created for the purpose of observing the Sun and serving as a warning system for possibly dangerous solar activity and space weather.
Some background on sunspots:
“Sunspots are temporary phenomena on the photosphere of the Sun that appear visibly as dark spots compared to surrounding regions. They are caused by intense magnetic activity, which inhibits convection by an effect comparable to the eddy current brake, forming areas of reduced surface temperature. Like magnets, they also have two poles.”
“Although they are at temperatures of roughly 3000–4500 K (2727–4227 °C), the contrast with the surrounding material at about 5,780 K (5,510 °C) leaves them clearly visible as dark spots, as the luminous intensity of a heated black body (closely approximated by the photosphere) is a function of temperature to the fourth power. If the sunspot were isolated from the surrounding photosphere it would be brighter than an electric arc. Sunspots expand and contract as they move across the surface of the Sun and can be as large as 80,000 kilometers (50,000 mi) in diameter, making the larger ones visible from Earth without the aid of a telescope. They may also travel at relative speeds (“proper motions”) of a few hundred meters per second when they first emerge onto the solar photosphere.”
“Manifesting intense magnetic activity, sunspots host secondary phenomena such as coronal loops (prominences) and reconnection events. Most solar flares and coronal mass ejections originate in magnetically active regions around visible sunspot groupings. Similar phenomena indirectly observed on stars are commonly called starspots and both light and dark spots have been measured.”
Image Credits: NASA/SDO/AIA/HMI/Goddard Space Flight Center; Sunspot via Wikimedia Commons
Keep up to date with all the most interesting green news on the planet by subscribing to our (free) Planetsave newsletter.