Sun's magnetic field about to flip

ORIGINAL: ABC
Ian O'Neill
Thursday, 8 August 2013
Discovery News

As the Sun approaches solar max the magnetic field is at its most stressed (NASA/SDO)

Every 11 years or so, the Sun does something quite profound - its magnetic field completely swaps polarity. This event occurs at the peak of the solar cycle, heralding the mid-point and the most active phase of Solar Cycle 24.

"It looks like we're no more than three to four months away from a complete field reversal," says solar physicist Todd Hoeksema of Stanford University. "This change will have ripple effects throughout the solar system."

Solar astronomers have been keeping a close eye on the magnetic conditions in the lowest regions of the Sun's atmosphere, measuring its magnetic field strength and direction.

"The Sun's polar magnetic fields weaken, go to zero, and then emerge again with the opposite polarity. This is a regular part of the solar cycle," says solar physicist Phil Scherrer, also of Stanford University.

Hoeksema and Scherrer work at Stanford's Wilcox Solar Observatory, one of the few observatories on the planet that is capable of acquiring solar magnetograms.

Wilcox has been monitoring the Sun's polarity since 1976, seeing in three "grand reversals" from three solar cycles. This will be its fourth and excitement is mounting, especially as we're only a few months away from complete reversal.

The solar cycle ebbs and flows over an approximate 11-year period. From "solar minimum" to "solar maximum," our nearest star's internal magnetic field gets wound up by the Sun's differential rotation. Differential rotation means that the Sun rotates faster at the equator than it does at the poles, dragging the magnetic field - like an elastic band - that is embedded in the superheated plasma.

As the Sun approaches solar max (as it is now) the magnetic field is at its most stressed, causing magnetic arcs to be forced from the solar interior and into the lower corona.

It is during this period that space weather is at its most ferocious, creating beautiful aurorae at the Earth's poles caused by an intensified solar wind blasting energetic particles into the Earth's magnetosphere.

This is also a period of intensified flare and coronal mass ejection (CME) activity, potentially damaging satellites and interfering with communications on the ground.

A visible marker of the progression of the solar cycle is the appearance of sunspots - dark blemishes in the Sun's photosphere, marking the location of active regions and potential sites of magnetic eruptions.

Tipping point

So, as we experience solar maximum, the Sun's interior reaches a tipping point in its magnetic polarity, signified by a magnetic field weakening.

When the field does switch polarity, it's not just a local event. The Sun's magnetic field projects from the Sun and sweeps throughout the Sun's environment - the heliosphere. As the field flips inside the Sun, so does the interplanetary magnetic field, causing the magnetic field and associated electric "current sheet" to ripple and warp.

Although the underlying reasons for the solar cycle are yet to be understood, Hoeksema and Scherrer know what's going to happen next.

"The Sun's north pole has already changed sign, while the south pole is racing to catch up," says Scherrer. "Soon, however, both poles will be reversed, and the second half of Solar Max will be underway."

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Dramatic solar tsunamis reveal magnetic secrets in sun's corona

ORIGINAL: LATimes

By Amina Khan

July 12, 2013

This image from the Solar Dynamics Observatory shows the "quiet corona" and upper transition region of the sun. A study tracking solar tsunamis through the sun's plasma shows that the quiet corona may not be so quiet after all. (Solar Dynamics Observatory / NASA)

If tsunamis on Earth don’t seem terrifying enough, imagine the power of such a monstrous wave on the sun -- bigger, faster and made of searing plasma. Scientists have spotted two solar tsunamis that have allowed them to accurately measure the sun's magnetic field. The results, published by the journal Solar Physics, should help researchers better understand the makeup of the sun’s "quiet corona" and help predict when coronal mass ejections threaten Earth.

Solar tsunamis, spotted initially in 1997, are caused when a coronal mass ejection is hurled from the sun out into space. The eruption of charged matter pushes the surrounding plasma outward, sending out a circular wave that can travel 620 miles per second and cover half the sun’s surface in an hour, said study lead author David Long, a solar physicist at University College London.

Using NASA’s Solar Dynamics Observatory and the Japanese Hinode spacecraft, the researchers managed to capture two solar tsunamis in action, rising about 43,500 miles high and speeding along at roughly 250 miles per second. Having data from both spacecraft was key. Using NASA’s spacecraft, they tracked the tsunami by watching the ultraviolet light given off as the wave progressed. Using data from the Japanese spacecraft, they determined the density of the matter it was traveling through.

“In both of these events we were just in the right place — wasn’t too close, wasn’t too far away,” Long said.

That’s because as the tsunami spreads outward somewhat like a ripple, it gets distorted by the material it passes through. It will travel faster in denser areas and slower in less dense ones, Long said, because in dense areas the molecules are tightly packed together and can quickly relay the wave along. In sparser areas there might be a slight delay before one molecule runs into the next. The resulting raggedy circles showed that the wave was running through patchy star stuff rather than a smooth, homogeneous medium.

Together, this information allowed the scientists to determine what the density, and the magnetic field, looked like in the less active areas of the sun’s atmosphere known as the quiet corona.

"The fact that it gets deformed means that there are variations in the magnetic field of the solar atmosphere, which was very interesting," Long said. "There’s a lot more going on there than we originally thought."

Understanding a solar tsunami could also help scientists better predict the arrival of a coronal mass ejection. If such a burst of charged particles reaches Earth, it can wreak havoc on the globe’s power, electronics and navigation systems.

"If a coronal mass ejection is coming straight at you, it’s very difficult to measure its speed; it’s very difficult to measure how powerful it is," Long said. "So we are hoping that by looking at these waves, we’d be able to tell something about coronal mass ejections, which would be very useful for space weather forecasting."

amina.khan@latimes.com

Sampling MIT at the MIT Museum: Water Splitting

ORIGINAL: MIT

MIT Professor Daniel Nocera and his research team are in a race to make inexpensive energy from the sun and they want to do it soon. Using plant photosynthesis as their inspiration, this exhibit shows how they can now use the suns energy to split water into hydrogen and oxygen gases in a safe and simple way. 

Daniel Nocera describes new process for storing solar energy

In a revolutionary leap that could transform solar power from a marginal, boutique alternative into a mainstream energy source, MIT researchers have overcome a major barrier to large-scale solar power: storing energy for use when the sun doesn't shine.

Watch 3 years of solar activity in a 3-minute video

ORIGINAL: LA Times

By Deborah Netburn

April 24, 2013, 4:27 p.m.

Thanks to NASA, you can now stare at the sun for three minutes straight.

No, don't run outside and look up. Instead, check out the clip above that condenses three years of sun images into a hypnotic three-minute video that shows our closest star rotating on its axis, radiating energy and light.

The images in the video were taken by the Solar Dynamics Observatory, a NASA satellite that launched three years ago in 2010, with the express purpose of helping scientists better understand the sun and how its magnetic fields shift and change. 

To that end, the Solar Dynamics Observatory is constantly monitoring the sun, including snapping an image of it every 12 seconds in 10 different wavelengths.

The video above was created by stitching together two of those images per day over a three-year period. The images in the video were taken in the extreme ultraviolet range and represent solar material at temperatures of about 600,000 Kelvin. Each image is displayed for two frames. 

That spinning motion you see is the sun's 25-day rotation, and over the course of the video, you should be able to see solar activity grow as the sun nears the pinnacle of its 11-year solar cycle.

At the 00:30 mark and at 2:28 you can spot a partial eclipse of the sun by the moon,
at 1:11 you will see the Aug. 9, 2011, X6.9 Flare, which was the largest solar flare of this solar cycle, and at 1:51 you will see the transit of Venus.

The sun does appear to subtly increase and decrease in size over the course of the video, but that's because the distance between the Solar Dynamics Observatory and the sun has changed a bit over time. 

Admittedly, the video may seem repetitive to some viewers, but if you can stick it out till the end, you are treated to a four-wavelength view, which shows how different the sun appears depending on what wavelengths you are measuring.

Huge 'Solar Tornado' Twists Across Sun's Surface in New Video

ORIGINAL: Space

SPACE.com Staff

Date: 29 March 2012 Time: 07:00 AM ET

NASA's Solar Dynamics Observatory spacecraft observed a "tornado" as wide as five Earths raging on the sun's surface on Sept. 25, 2011. This sequence of photos follows the tornado over 2 1/2 hours.

CREDIT: NASA/SDO/AIA/Aberystwyth University/Li/Morgan/Leonard

A NASA spacecraft has captured video of a massive solar "tornado" five times wider than the Earth twisting its way across the surface of the sun.

NASA's Solar Dynamics Observatory (SDO) looked on as the huge, swirling storm raged on Sept. 25, 2011, spinning solar gas at speeds up to 186,000 mph (300,000 kph), researchers said. Here on Earth, tornado wind speeds top out at around 300 mph (483 kph).

"This is perhaps the first time that such a huge solar tornado is filmed by an imager," Xing Li of Aberystwyth University in Wales, who analyzed the SDO footage, said in a statement. "Previously, much smaller solar tornadoes were found by the [NASA/European Space Agency] SOHO satellite. But they were not filmed."

Li and other researchers will present a movie of the tornado Thursday (March 29) at the 2012 National Astronomy Meeting in Manchester, the United Kingdom.

SDO's instruments saw gases as hot as 3.6 million degrees Fahrenheit (2 million degrees Celsius) rise from a dense solar structure called a prominence, then travel about 124,000 miles (200,000 kilometers) along a spiral path into the upper solar atmosphere, researchers said.

Unlike Earth's tornados, which are driven by wind, solar twisters are shaped by our star's powerful magnetic field. They often occur in concert with violent explosions of solar plasma known as coronal mass ejections, or CMEs. Some researchers think the tornados may help trigger CMEs, which can streak through space at several million miles per hour.

CMEs that hit Earth can wreak havoc on our planet, causing temporary disruptions in GPS signals, radio communications and power grids. They also typically supercharge the dazzling light shows near Earth's poles known as the northern and southern lights.

The $850 million SDO spacecraft, which launched in February 2010, is the first in a fleet of NASA efforts to study our sun. The probe's five-year mission is the cornerstone of a NASA science program called Living with a Star, which aims to help researchers better understand aspects of the sun-Earth system that affect our lives and society.

The sun is currently in an active period of its 11-year weather cycle. The current cycle is known as Solar Cycle 24 and will peak in 2013.

Follow SPACE.com for the latest in space science and exploration news on Twitter @Spacedotcom and on Facebook.

No ocurría hace 120 años. Venus cruza el Sol. Martes 5 de Junio de 2012

ORIGINAL: Parque Explora

01 de Junio de 2012

No ocurría hace 120 años. Venus cruza el Sol

Todos los Astrónomos del mundo tendrán sus ojos puestos en este fenómeno único. ¡Acompáñalos!

El Parque Explora y el Planetario de Medellín invitan este martes 5 de junio a las 5 pm, desde el Parque de los Deseos, al cubrimiento de tránsito de venus, uno de los eventos astronómicos más importante del siglo.Primer evento del programa "El ojo celeste: astronomía en el Parque" 

Acompáñenos en esta actividad que será comentada por los profesores del pregrado de Astronomía de la Universidad de Antioquia Jorge Zuluaga y Pablo Cuartas, y por el presidente de la Sociedad Antioqueña de Astronomía León Jaime Restrepo. 

Poder ver el paso de Venus cruzando delante del Sol es una verdadera coincidencia astronómica que sólo ocurre un par de veces, más o menos, cada 120 años. El próximo transito sucederá el 5 de junio de este año, pero no volverá a ocurrir hasta el 2.117 

¡Qué no le pase lo que le pasó a Galileo!

Si las condiciones del cielo lo permiten realizaremos observaciones con filtros solares.

No mire el Sol directamente, 

recomendamos utilizar filtros de soldadura 14 ó 16, los cuales brindan una óptima protección a sus ojos. El evento será retransmitido en la pantalla gigante del Planetario a partir de las 6:45 pm

¿Qué es el tránsito de Venus?

Ocurre cuando Venus pasa por delante del disco solar, o sea, cuando la Tierra, Venus y el Sol están alineados. Este fenómeno sólo ocurre en los meses de junio y diciembre. Durante el tránsito se podrá observar un disco circular negro que atraviesa la brillante superficie solar, este recorrido puede durar varias horas.

¿Con que frecuencia ocurre?

Los tránsitos de Venus son poco frecuentes, en un lapso de 243 años, sólo ocurren 4. El ciclo de 243 años es relativamente estable, pero el número de tránsitos y el intervalo entre uno y el siguiente varían con el tiempo debido a las perturbaciones que los planetas jovianos* (y la Tierra) producen en la órbita de Venus.

El último tránsito ocurrió el 6 de diciembre de 1.882 y el próximo sucederá el 8 de diciembre de 2117.

¿En qué lugares de la Tierra será visible?

El tránsito completo se verá en el noroeste de América del Norte, Hawai, el Pacífico occidental, el norte de Asia, Japón, Corea, el este de China, Filipinas, el este de Australia y Nueva Zelanda.

El tránsito parcial se verá en la mayor parte de América del Norte, el Caribe y el noroeste de América del Sur, Asia central, Oriente Medio, Europa y el este de África.

¿Se podrá ver en Medellín?

Si las condiciones del tiempo lo permiten se podrá observar el comienzo del tránsito desde las 5:09 pm hasta las 5:50 pm hora en la que se oculta el Sol por el occidente tomando como referencia el Parque Explora.

Clean Drinking Water for Everyone

ORIGINAL: MTU
April 30, 2012
By Marcia Goodrich

Leaving bottles of water in the sun kills pathogens--but only if the water is transparent. Michigan Tech's Joshua Pearce has devised a simple way to clarify water, so even muddy water could be made safe for drinking. SODIS Eawag photo

Nearly 80 percent of disease in developing countries is linked to bad water and sanitation. Now a scientist at Michigan Technological University has developed a simple, cheap way to make water safe to drink, even if it’s muddy.

It’s easy enough to purify clear water. The solar water disinfection method, or SODIS, calls for leaving a transparent plastic bottle of clear water out in the sun for six hours. That allows heat and ultraviolet radiation to wipe out most pathogens that cause diarrhea, a malady that kills 4,000 children a day in Africa.

It’s a different story if the water is murky, as it often is where people must fetch water from rivers, streams and boreholes. “In the developing world, many people don’t have access to clear water, and it’s very hard to get rid of the suspended clay particles,” says Joshua Pearce, an associate professor of materials science and engineering. “But if you don’t, SODIS doesn’t work. The microorganisms hide under the clay and avoid the UV.”

Thus, to purify your water, you first have to get the clay to settle out, a process called flocculation. Working with student Brittney Dawney of Queen’s University in Ontario, Pearce discovered that one of the most abundant minerals on Earth does this job very well: sodium chloride, or simple table salt.

Salt is inexpensive and available almost everywhere. And it doesn’t take very much to make muddy water clear again.

“The water has a lower sodium concentration than Gatorade,” Pearce says. This would still be too much salt to pass muster as American tap water, but American tap water is not the alternative.

“I’ve drunk this water myself. If I were somewhere with no clean water and had kids with diarrhea, and this could save their lives, I’d use this, no question,” he says.

Salt works best when the suspended particles are a type of clay called bentonite. The technique doesn’t work as well with other kinds of clay. However, by adding a little bentonite with the salt to water containing these different clays, most of the particles glom together and settle out, creating water clear enough for SODIS treatment.

Pearce and Dawney are running more tests on water containing various types of clays, and they are also investigating different soil types across Africa to see where their methods might work the best.

Their paper “Optimizing the Solar Water Disinfection (SODIS) Method by Decreasing Turbidity with NaCl” has been accepted for publication in the Journal of Water, Sanitation, and Hygiene for Development and will appear in June. A preprint of the paper is available here.

Michigan Technological University (www.mtu.edu) is a leading public research university developing new technologies and preparing students to create the future for a prosperous and sustainable world. Michigan Tech offers more than 130 undergraduate and graduate degree programs in engineering; forest resources; computing; technology; business; economics; natural, physical and environmental sciences; arts; humanities; and social sciences.

Imágenes de la Tormenta Solar en el Norte de Noruega

ORIGINAL: Northern Lights Photography

¡El Sol está despierto!

El sábado pasado (21 de enero de 2012) fue el día del regreso-del-sol aquí en Tromsø, cuando el Sol se podía ver sobre el horizonte por primera vez desde noviembre del año pasado. Debido a las montañas que bloquean la vista no he visto el Sol real todavía, pero su luz reflejada se podía ver en las laderas de montaña y pronto llegará aún más alto.

El Sol, sin embargo, hizo mucho más que "sólo" volver este fin de semana - que también envió una eyección de masa llamada coronal (CME), que alcanzó el campo magnético de la Tierra y ha producido algunas luces del norte muy intensas en todo el círculo polar ártico.

Así se veía el cielo parecía, visto desde fuera Kvaløya Tromsø. Las imágenes son del 21 de enero, 22 y 23.

Auroras y el planeta Júpiter en la paso de Ersfjorden, Noruega

Las Pléyades y Júpiter enmarcados por las auroras y las montañas de Kvaløya

Corona de Luz Nórdica en verde y rojo

Auroras rojas

Vista desde el exterior de Kvaløya el 22 de enero

Tormenta Solar en el Norte de Noruega por Fredrik Broms en Vimeo.
Secuencia de imágenes a intervalos de tiempo de la tormenta solar que está impactando la atmósfera de la Tierra los días 21-23 de enero de 2012. La secuencia completa fue capturad dentro de este período de tiempo en varios lugares en Kvaløya fuera de Tromsø en el norte de Noruega
 Copyright Notice:
All rights reserved to Fredrik Broms - Northern Lights Photography - www.northernlightsphotography.no

Actualización - Desarrollo de la Tormenta Solar (24 de enero de 2012)

Durante los últimos tres días, las luces del norte se han visto muy intensas en todo el círculo polar ártico.

Como se predijo, una fuerte eyección de masa coronal (CME) alcanzó el campo magnética de la Tierra hace apenas una hora aproximadamente a las 1500 UT, según lo informado por mi colega Stamnes Rob en el Centro de Polar de Luz en Lofoten, Noruega.

Esto significa que es muy probable que haya auroras vistosas en las próximas horas, así que si tiene el cielo despajeado, sál a echar un vistazo al cielo nocturno!

A continuación se muestra una secuencia de video que hice de la tormenta solar de 21-23 Enero 2012 - las de esta noche podrían ser aún mejores!