European Association for Astronomy Education

Source: Universe Today

Credit: NASA Goddard Space Flight Center

How far is the Sun? It seems as if one could hardly ask a more straightforward question. Yet this very inquiry bedeviled astronomers for more than two thousand years.

Certainly it’s a question of nearly unrivaled importance, overshadowed in history perhaps only by the search for the size and mass of the Earth. Known today as the astronomical unit, the distance serves as our reference within the solar system and the baseline for measuring all distances in the Universe.

Thinkers in Ancient Greece were among the first to try and construct a comprehensive model of the cosmos. With nothing but naked-eye observations, a few things could be worked out. The Moon loomed large in the sky so it was probably pretty close. Solar eclipses revealed that the Moon and Sun were almost exactly the same angular size, but the Sun was so much brighter that perhaps it was larger but farther away (this coincidence regarding the apparent size of the Sun and Moon has been of almost indescribable importance in advancing astronomy). The rest of the planets appeared no larger than the stars, yet seemed to move more rapidly; they were likely at some intermediate distance. But, could we do any better than these vague descriptions? With the invention of geometry, the answer became a resounding yes.(...)
Read the rest of How Did We Find the Distance to the Sun?

Source: MESSENGER Press Release

Artist's impression  of the MESSENGER Spacecraft.
Image credits: NASA /MESSENGER.

MESSENGER Completes Its 2,000th Orbit of Mercury, Provides Data on Solar Magnetic Field

MESSENGER began its 2,000^th orbit around Mercury earlier this week, on May 22. The spacecraft completed its primary mission on March 17, 2012, and its first extended mission on March 17, 2013. The team is awaiting word from NASA on a proposal for a second extended mission. In the meantime, instruments aboard the spacecraft continue to gather new data on Mercury and its environment.

From May 6 to May 14, MESSENGER traversed a superior solar conjunction, during which the spacecraft was on the far side of the Sun from Earth. Scientists used the opportunity to measure the characteristics of the solar magnetic field from the Faraday rotation of its radio-frequency carrier.

“We found the orientation of the magnetic field within a coronal mass ejection (CME) that crossed the line of sight on May 10,” says Elizabeth Jensen, of the Planetary Science Institute in Tucson, Arizona. “We saw the rotation of the plane of polarization of MESSENGER’s radio-frequency signal as it moved deeper into the corona, giving information on the Sun's magnetic field configuration on May 11; and on May 12, we saw magnetohydrodynamic waves, a very important mode of energy transfer in the corona.”

Solar storms cause communications disruptions, expose spacecraft and personnel in airplanes to radiation, and threaten electrical grids. Jensen says that the observations of the CME demonstrate the utility of this technique to predict the threat of solar storms headed toward Earth almost immediately after they erupt.

“Understanding the accuracy of models for the solar magnetic field and solar wind generation requires testing,” she says. “Although other methods can be used in active regions, Faraday rotation is the only way to test the magnetic field models in the largest part of the corona where the solar wind is accelerating.”

At its closest point to Mercury, MESSENGER will be about 447 kilometers (277.8 miles) above a point near 83.1° N latitude. Since its most recent orbit-correction maneuver on April 20, 2012, the spacecraft has completed three orbits of Mercury every day. At this rate, says mission trajectory lead James McAdams of the Johns Hopkins University Applied Physics Laboratory (APL) in Laurel, Maryland, the spacecraft will reach its 3,000^th orbit around Mercury on April 20, 2014.

Source: ESA

The Sun's idea. Image taken with SOHO’s LASCO 3.
Image credits: SOHO/LASCO (ESA & NASA).

A light bulb-shaped eruption leaps from the Sun and blasts into space in this archival image from the ESA/NASA Solar and Heliospheric Observatory, SOHO. (read more)

Source: NASA

Hi-C will image the Sun at a 5x higher resolution
(0.1 arcsec/pixel image) than any previously done.
Image credits: NASA

A telescope launched July 11 aboard a NASA sounding rocket has captured the highest-resolution images ever taken of the sun's million-degree atmosphere called the corona. The clarity of the images can help scientists better understand the behavior of the solar atmosphere and its impacts on Earth's space environment.

"These revolutionary images of the sun demonstrate the key aspects of NASA's sounding rocket program, namely the training of the next generation of principal investigators, the development of new space technologies, and scientific advancements," said Barbara Giles, director for NASA's Heliophysics Division at NASA Headquarters in Washington.

Launched from White Sands Missile Range in New Mexico, the 58-foot-tall sounding rocket carried NASA's High Resolution Coronal Imager (Hi-C) telescope. Weighing 464 pounds, the 10-foot-long payload took 165 images during its brief 620-second flight. The telescope focused on a large active region on the sun with some images revealing the dynamic structure of the solar atmosphere in fine detail. These images were taken in the extreme ultraviolet wavelength. This higher energy wavelength of light is optimal for viewing the hot solar corona.

"We have an exceptional instrument and launched at the right time," said Jonathan Cirtain, senior heliophysicist at NASA's Marshall Space Flight Center in Huntsville, Ala. "Because of the intense solar activity we're seeing right now, we were able to clearly focus on a sizeable, active sunspot and achieve our imaging goals."

The telescope acquired data at a rate of roughly one image every 5 seconds. Its resolution is approximately five times more detailed than the Atmospheric Imaging Assembly (AIA) instrument flying aboard NASA's Solar Dynamics Observatory (SDO). For comparison, AIA can see structures on the sun's surface with the clarity of approximately 675 miles and observes the sun in 10 wavelengths of light. Hi-C can resolve features down to roughly 135 miles, but observed the sun in just one wavelength of light.

The high-resolution images were made possible because of a set of innovations on Hi-C's optics array. Hi-C's mirrors are approximately 9 1/2 inches across, roughly the same size as the SDO instrument's. The telescope includes some of the finest mirrors ever made for space-based instrumentation. The increase in resolution of the images captured by Hi-C is similar to making the transition in television viewing from a cathode ray tube TV to high definition TV.

Initially developed at Marshall, the final mirror configuration was completed with inputs from partners at the Smithsonian Astrophysical Observatory (SAO) in Cambridge, Mass., and a new manufacturing technique developed in coordination with L-3Com/Tinsley Laboratories of Richmond, Calif.

The high-quality optics were aligned to determine the spacing between the optics and the tilt of the mirror with extreme accuracy. Scientists and engineers from Marshall, SAO, and the University of Alabama in Huntsville worked to complete alignment of the mirrors, maintaining optic spacing to within a few ten-thousandths of an inch.

NASA's suborbital sounding rockets provide low-cost means to conduct space science and studies of Earth's upper atmosphere. In addition, they have proven to be a valuable test bed for new technologies for future satellites or probes to other planets.

Launched in February 2010, SDO is an advanced spacecraft studying the sun and its dynamic behavior. The spacecraft provides images with clarity 10 times better than high definition television and provides more comprehensive science data faster than any solar observing spacecraft in history.

3rd class girls St Pauls Senior Girls NS Greenhills Dublin 12
We built the sun at school

3rd class girls St Pauls Senior Girls NS Greenhills Dublin 12
We built the sun at school

St Pauls Senior Girls National School in Greenhill’s Dublin 12 is just a few minutes’ walk from the house where I grew up.  It was fortuitous to have the opportunity to carry out my third Action Sun for a school in this area.

On June 25th 47 young girls from third class, took part in building the sun. This was a very positive group all eager to get going and get busy. Streamers of orange and red paper flew through the air in vast amounts. In a short time the photosphere began to grow in the schools courtyard.

The activity of Action Sun supports the school curriculum in its art as it uses mixed media to create the sun. The program uses paint and paper to convey activity and explosive movement on the solar disc. Action Sun also supports primary school art as it enables children to use the characteristics of the materials to make structures and features on the solar disc. Making the sun in this way is both creative and explorative. Learning a little science through the arts facilitates the use of many kinds of intelligences.  The learning process in the making is as valuable as the finished suns. Textures and spatial   organisation also comes into the creation of this work. The girls at St Pauls School were very good at working as a group, helping each other out. They also made good decisions during the activity which showed they were an excellent team. This is kinesthetic learning, learning by doing.

Action Sun compliments science in the primary school curriculum on several levels.   A short information talk in between making the suns features informs the children about our suns role in the solar system. We talk about the scale of the sun and the Earth. We talk about the energy of the sun and its function in relation to the other planets.  The mini talks make sure that the children understand that the sun is our main source of heat and light.  By building the sun the children learn by hands on investigation. The children literally explore the physical features of the sun with their hands in mini scale. A quick review of the evaluation sheets shows the quality of the learning. Several children not only drew sketches of the complex sun but also put in arrows to the different features and labelled them all correctly. The action of throwing the paper was very popular, signing their names was also a highlight and for some children carrying the sun into the hall was the stand out moment of the day.

When I look at the sun in my solar telescope I see a huge amount of detail and very often in the past I have shared that view with children. However it takes a long time to show this view to a large group as the sun presents as a small disc with tiny features. It is difficult for children to comprehend the enormous scale of our nearest star.  I put Action Sun together to bridge that gap and help more people achieve some understanding of this wonderful star in safety with a big fun element.

The features of the sun itself were totally new to this young group, but at the end of the programme words like photosphere, chromosphere, filaments, prominences and sunspots were all a little more familiar. We closed our eyes at the end of the build and held our faces up to the sun to feel its heat and remind ourselves that it takes eight minutes for its light to get to us here on Earth, a 93 million mile smile. Building the sun took about 90 minutes. The 7.9 X 4.9 meter tarpaulin was pre prepared at home using four litres of matte black masonry paint. During  the activity we used approx 3,500 individual pre cut  pieces of crepe paper ,15 litres of washable  PVA glue, 6 litres of yellow paint , 1 litre of red paint,  plus the energy of forty seven eight and nine year old third class girls.

My thanks to Sarah Jayne Reid for setting up Action Sun at St Pauls and to Phil Curran for all her efforts prior to, during and post the build. Thanks to Ms Keating, Ms Daly and Principal Sr Maureen for their support during the activity.  NASA Sun Earth Day bookmarks, posters and other educational material were provided to the teachers.  The solar feature data for this Action Sun was an observation of the disc made from my PST earlier that morning.  The Solar Dynamics Observatory website was pointed out to the girls so they could continue to watch the sun safely.

More images on my blog here

Whats Up for July 2012 from Jane Houston Jones

Source: ESA

A large sunspot region (AR1429) unleashes an X5 class flare.
Image credits: ESA/NASA/SOHO/SDO.

A pair of unusually large solar flares early yesterday generated a Coronal Mass Ejection that will reach Earth around mid-day today. It will likely cause at least a strong geomagnetic storm that could affect satellites in space and trigger auroral displays.(read more)

Source: ESA

Large M8.3-class solar flare seen by ESA/NASA SOHO satellite 23 January.
Image credits: ESA/NASA.

A large solar flare yesterday triggered a coronal mass ejection travelling at 1400 km/s that will reach Earth today. An energetic eruption of this level can disrupt satellites, so operation teams at ESA and other organisations are closely monitoring the storm. (read more)

Source: NASA Science News

Image credits: NASA.

Last month, a massive solar storm launched itself toward Mars just as NASA's new rover, Curiosity, was blasting off from Cape Canaveral in the same direction. The coincidence heralds a new job for the multi-talented rover: For the next 9 months, Curiosity will monitor solar storms en route to the Red Planet. (read more)

Source: NASA Science News

Sun at 171 Angstrom. Image credit: NASA/SDO.

NASA-supported researchers say that solar flares have been keeping a secret. The new finding, reported in the Astrophysical Journal, suggests that explosions on the sun could affect Earth even more than previously thought. (read more)

Source: NASA/SDO

Sun at 171 Angstrom. Image credit: NASA/SDO.

NASA's Solar Dynamics Observatory, or SDO, has provided scientists new information about solar flares indicating an increase in strength and longevity that is more than previously thought.

Solar flares are intense bursts of radiation from the release of magnetic energy associated with sunspots. They are the solar system's largest explosive events and are seen as bright areas on the sun. Their energy can reach Earth's atmosphere and affect operations of Earth-orbiting communication and navigation satellites.

Using SDO's Extreme ultraviolet Variability Experiment (EVE) instrument, scientists have observed that radiation from solar flares continue for up to five hours beyond the main phase. The new data also show the total energy from this extended phase of the solar flare's peak sometimes has more energy than the initial event. (read more)

Source: NASA Science News

A wide-angle movie recorded by NASA's STEREO-A spacecraft shows a
solar storm traveling all the way from the sun to Earth and engulfing our planet.
A 17 MB Quicktime zoom adds perspective to the main 40 MB Quicktime movie.

For the first time, a spacecraft far from Earth has turned and watched a solar storm engulf our planet. The movie, released today during a NASA press conference, has galvanized solar physicists, who say it could lead to important advances in space weather forecasting.(Read more)

Credit: NASA SDO - YouTube

In the early hours of July 30, 2011 a fairly strong, but brief, M9-class solar flare occurred on Active Region 1261. Because it was brief it appears not to have hurled a large coronal mass ejection (CME) outwards. Additional analysis are underway.

Source: NASA/SDO

Jets, known as spicules, captured in an SDO image on April 25, 2010.
Image credits: NASA/SDO/AIA

Like giant strands of seaweed some 32,000 miles high, material shooting up from the sun sways back and forth with the atmosphere. In the ocean, it's moving water that pulls the seaweed along for a ride; in the sun's corona, magnetic field ripples called Alfvén waves cause the swaying.

For years these waves were too difficult to detect directly, but NASA's Solar Dynamics Observatory (SDO) is now able to track the movements of this solar "seaweed" and measure how much energy is carried by the Alfvén waves. The research shows that the waves carry more energy than previously thought, and possibly enough to drive two solar phenomena whose causes remain points of debate: the intense heating of the corona to some 20 times hotter than the sun's surface and solar winds that blast up to 1.5 million miles per hour.(read more)

Source: NASA Science News

Earth-orbiting satellites detected a flash of X-rays coming from the western edge of the solar disk. Registering only "M" (for medium) on the Richter scale of solar flares, the blast at first appeared to be a run-of-the-mill eruption--that is, until researchers looked at the movies.(read more)

Source: ESA News

M2.5-class solar flare observed by Proba-2's SWAP instrument.
Image credits: ESA/ROB.

ESA’s Proba-2 small Sun-watcher was among the flotilla of satellites on watch as the Sun erupted spectacularly this week. (read more)

Source: Space Daily

An unusual solar flare observed by a NASA space observatory on Tuesday could cause some disruptions to satellite communications and power on Earth over the next day or so, officials said.

The potent blast from the Sun unleashed a firestorm of radiation on a level not witnessed since 2006, and will likely lead to moderate geomagnetic storm activity by Wednesday. (read more)

Source: SOHO Pick of the Week

The STEREO (Ahead) spacecraft observed as a photogenic, solar prominence erupted and broke out into space over about 18-hour period (May 13, 2011). Prominences, notoriously unstable structures, are cooler clouds of gas that float above the Sun's surface, tethered there by magnetic forces. They often erupt and race into space like this one did. The Sun here is being observed in extreme UV light. (view source)

Source: NASA News
YouTube Video: NASA Science Casts

Back in 2008, the solar cycle plunged into the deepest minimum in nearly a century. Sunspots all but vanished, solar flares subsided, and the sun was eerily quiet.

With a burst of solar flares and Northern Lights, the sun is waking up from a three-year slumber.(read more)



Children from St Cronans Stargazers draw moon phases

The Big Moon Ball Project – A work in progress

The Moon? The Moon? How on Earth do you explain the Moon to small children?  In many other talks I had done so in graphic from and with images but wanted to try something different. I figured I would have a go at an interactive workshop in a field, as one would of course.

Made me a Moon ball and put it on a stand, borrowed a super two million candle torch, put it on a stand.  Then I invited my new astronomy group St Cronans Stargazers to join me at our usual place.  As it was midterm a small but smiling group turned up, perfect for a first run!  We pretended the torch was the sun and the children were the Earth and I became the Moon.  For the first orbit of the Earth I spoke about the phase they see from the Earth as they looked at me (the Moon Ball) moving from New to First Quarter, then Full, then Last Quarter, then back to New.

The children got the idea very quickly as the sun (torch) illuminated the phases while they (the Earth) turned in unison in the field at the end of my road. The Big Moon Ball beamed the moons phases into their eyes.  Clip boards and paper were provided for the second orbit of the Earth .The children sketched the four main Moon phases as they happened and wrote down the names. The parents were very helpful, standing at the points of the phases and also helping the children see their clipboards and their drawings in the dark.

Of course this workshop would be so much more powerful if the Moon was in the sky at the same time. I am continuing to develop the activity; it suits the Irish cloudy sky syndrome and is also an indoor workshop.  Every child wanted to hold the Moon Ball and help put it in the car afterwards. A whole bunch of fun was over in a blink the children had lovely practical drawings for their folders, and were on their way to understanding the Moons movements.

The Big Moon Ball Project was welcomed by Engineers Ireland as part of Engineers Week Ireland
Huge thanks to my husband Bernard for help with the sun and for taking the photographs.
The Moon Ball is getting an upgrade, the far side is being painted in now and the near side is developing more details, craters, rays and mountains.  More images on my website here

Cool News /  Hot Stuff

NASA Solar System Exploration Page I am really delighted and honoured to have  my Solar Dynamics Observatory  inspired painting on the site for the month of March ,check it out. !!

Deirdre Kelleghan

Source: NASA News

Artistic cutaway view of the Sun, were the Great Conveyor Belt appears
as a set of black loops connecting the stellar surface to the interior.
Credit: Andrés Muñoz-Jaramillo of the Harvard CfA.

When solar activity recently plunged into a century-class minimum, many experts were puzzled. Now a group of researchers say they have cracked the mystery of the missing sunspots.(read more)