Universe Today » Solar Astronomy

MESSENGER Solves Solar Flare Mystery

Nancy Atkinson — Tue, 27 Oct 2009 00:03:33 +0000

In a case of being in the right place at the right time, the MESSENGER spacecraft was able to capture a average-sized solar flare, allowing astronomers to study high-energy solar neutrons at less than 1 astronomical unit (AU) from the sun for the first time. When the flare erupted on Dec. 31, 2007, MESSENGER – on course for entering orbit around Mercury — was flying at about half an AU, said William C. Feldman, a scientist at the Planetary Science Institute. Previously, only the neutron bursts from the most powerful solar flares have been recorded on neutron spectrometers on Earth or in near-Earth orbit. The MESSENGER results help solve a mystery of why some coronal mass ejections produce almost no energetic protons that reach the Earth, while others produce huge amounts.
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Spacecraft Detects Mysterious "Ribbon" at Edge of Solar System

Nancy Atkinson — Thu, 15 Oct 2009 20:03:19 +0000

Accurate timing of the incoming ENAs allows the IBEX team to obtain a higher resolution in the latitudinal direction. The inset at right shows some of the fine detail of the ribbon. Credit: Southwest Research Institute (SwRI)

Since it launched a year ago, the Interstellar Boundary Explorer (IBEX) has been monitoring heliosphere and how our Sun interacts with and the local interstellar medium — the gas and dust trapped in the vacuum of space. The first results from the mission, combined with data from the Cassini mission, are showing the heliosphere to be different from what researchers have previously thought. Data show an unexpected bright band or ribbon of surprisingly high-energy emissions. "We knew there would be energetic neutral atoms coming in from the very edge of the heliosphere, and our theories said there would be small variations in their emissions," said David McComas, IBEX Principal Investigator at a press conference on Thursday. "But instead we are seeing two-to-three hundred percent variations, and this is not entirely understood. Whatever we thought about this before is definitely not right."
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Two Equinox Sunspots

Nancy Atkinson — Wed, 23 Sep 2009 15:50:46 +0000

Two sunspots appeared on old Sol yesterday just as Earth's orbit ushered in the Autumnal Equinox. Two sunspots showing up at once hasn't happened in more than a year, and over 80% of the days in 2009 have been "sunspotless" during this deepest solar minimum in a century. Spaceweather.com had a great picture, below, of the first sunspot that appeared, #1026, taken by astrophotographer Peter Lawrence. Lawrence said there was a lot going on around the new sunspot. "The spot's dark core is surrounded by active fibrils and a swirling magnetic filament that gives the region a nice 3D appearance."
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Temporary Radiation Belt Discovered at Saturn

Nancy Atkinson — Mon, 14 Sep 2009 00:08:12 +0000

A new, temporary radiation belt has been detected at Saturn, located about 377,000 km from the center of the planet, near the orbit of the moon Dione. The temporary radiation belt was short-lived and formed three times in 2005. It was observed as sudden increases in the intensity of high energy charged particles in the inner part of Saturn's magnetosphere, in the vicinity of the moons Dione and Tethys, and likely was caused by a change in the intensities of cosmic rays at Saturn.
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July 22, 2009 Total Solar Eclipse from China – Let's Chase!

Tammy Plotner — Thu, 23 Jul 2009 04:02:38 +0000

Eclipse from Chongqing Municipality (Xinhua/Liu Chan)

The total solar eclipse which just occurred on the 22nd of July 2009 was the longest maximum duration of the 21st century. Not since Saros 1991 have astronomers and eclipse chasers been treat to such an event! Totality lasted over six and a half minutes at maximum. duration. The event started in India along the western shore near Surat moved towards Butan and reached the southern tip of Nepal and the northern edge of Bangladesh.

For other lucky astronomers like Vietnamese student Dang Anh Tuan at Hanoi National University of Education, the eclipse path also took the event over cities like Chengdu, Suining, Chonging, Wuhan, Xiaogan, Hangzhou, and Shanghai – and event which yielded five minutes of totality. Leaving Shanghai the shadow path raced across the ocean, to fall across islands such as Toshima and Akusaki south of Japan and eventually the Marshall islands. Where was the longest point? The maximum eclipse duration of 6 minutes and 43 seconds occurs far off the coast in the Pacific Ocean! Are you ready to become an eclipse chaser? Then follow me… (...)
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July 22, 2009 Total Solar Eclipse – Incoming News…

Tammy Plotner — Wed, 22 Jul 2009 14:41:23 +0000

July 22, 2009 Solar Eclipse Image Submitted By Bill Fish

The total solar eclipse which just occured on the 22nd of July 2009 was the longest in terms of maximum totality duration of the 21st century – lasting over six and a half minutes. Not since Saros 1991 have astronomers and eclipse chasers been treated to such a length of time! The eclipse footprint started in India along the western shore near Surat moved towards Butan and reached the southern tip of Nepal and the northern edge of Bangladesh. For other lucky astronomers, the eclipse path also took the event over the Chinese cities of Chengdu, Suining, Chonging, Wuhan, Xiaogan, Hangzhou, and Shanghai – yielding five minutes of totality. Leaving Shanghai the shadow raced across the ocean to fall across islands such as Toshima and Akusaki south of Japan and eventually the Marshall islands. Where did the longest time occur? The maximum eclipse duration of 6 minutes and 43 seconds was far off the coast in the Pacific Ocean! As I write this announcement, our readers are sending in their photos and stories to my home email (send them!!) and I just couldn't wait to show you some of the beginning results. It will take a short time to do a little translation work… But it's a small, wonderful world and this article will be updated very soon!

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New, Close-Up View Probes the Nature of Sunspots

Anne Minard — Fri, 19 Jun 2009 16:05:18 +0000

©UCAR, image courtesy Matthias Rempel, NCAR

Seriously, I don't think we should stare at this too long … but for scientists who plan to, this new, high-resolution view of a sunspot stands to unlock secrets of the Sun's mysterious energetics.

In the just-released image above, the interface between a sunspot's umbra (dark center) and penumbra (lighter outer region) shows a complex structure with narrow, almost horizontal (lighter to white) filaments embedded in a background having a more vertical (darker to black) magnetic field. Farther out, extended patches of horizontal field dominate. For the first time, scientists have modeled this complex structure in a comprehensive 3D computer simulation, giving scientists their first glimpse below the visible surface.

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The Case of the Missing Sunspots: Solved?

Anne Minard — Wed, 17 Jun 2009 18:31:00 +0000

The Sun has seen precious few sunspots (as shown in this NASA closeup) in the past year, and solar physicists have been working to understand why. Now, some think they have an answer.

According to work being presented this week at the meeting of the Solar Physics Division of the American Astronomical Society, a solar jet stream deep inside the Sun is migrating slower than usual through the star’s interior and it's at least associated with — if not causing — the current lull in sunspots and solar activity.

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Newsflash: Sunspot Appears!

Nancy Atkinson — Mon, 01 Jun 2009 22:08:13 +0000

OK, I admit – the headline is a little over the top. But the sun has been so quiet of late, that even a small sunspot can be exciting. There's been some debate whether this period of extreme solar calm is truly unusual, or just part of the natural cycle. But solar cycle models never predicted this low amount of activity. "It turns out that none of our models were totally correct," admitted Dean Pesnell of the Goddard Space Flight Center, a member of an international panel of experts that are now trying to predict what the next solar cycle will hold. "The sun is behaving in an unexpected and very interesting way."
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Cosmic Rays too Wimpy to Influence Climate

Anne Minard — Fri, 01 May 2009 18:31:48 +0000

Illustration Credit: Simon Swordy (U. Chicago), NASA

People looking for new ways to explain climate change on Earth have sometimes turned to cosmic rays, showers of atomic nuclei that emanate from the Sun and other sources in the cosmos.

But new research, in press in the journal Geophysical Research Letters, says cosmic rays are puny compared to other climatic influences, including greenhouse gases — and not likely to impact Earth's climate much.

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European, Chinese Satellites Watch Solar Storms Pummel Earth

Anne Minard — Wed, 29 Apr 2009 14:48:09 +0000

Scientists have long understood that satellites are at risk from bombardment by solar storms. Now, they've gotten a closer look at how the storms are punishing Earth's magnetosphere, leaving satellites exposed.

The movie above, and the solar flare video below, were released by the European Space Agency today, along with descriptions of two solar eruptions spotted using ESA’s four Cluster satellites and the two Chinese/ESA Double Star satellites.

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New Finding Shows Super-Huge Space Tornados Power the Auroras

Nancy Atkinson — Thu, 23 Apr 2009 20:45:27 +0000

If you think tornadoes on Earth are scary, newly found "space tornadoes" sound downright horrifying. But they are likely the power source behind the beautiful Northern and Southern Lights. A new finding by a cluster of five space probes – the THEMIS, or Time History of Events and Macroscale Interactions during Substorms show that electrical funnels which span a volume as large as Earth produce electrical currents exceeding 100,000 amperes. THEMIS recorded the extent and power of these electrical funnels as the probes passed through them during their orbit of Earth. Ground measurements showed that the space tornadoes channel the electrical current into the ionosphere to spark bright and colorful auroras on Earth.
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Solar Sigmoids Explained

Nancy Atkinson — Mon, 20 Apr 2009 21:38:16 +0000

S-shaped structures called 'Sigmoids' have been found in the outer atmosphere of the Sun — the corona. Sigmoids are thought to be a crucial part of explosive events like solar flares. Now a group of astronomers have developed the first model to reproduce and explain the nature of the different stages of a sigmoid’s life. Recently, the X-Ray Telescope (XRT) on board the Hinode space mission was used to obtain the first images of the formation and eruption phase of a sigmoid at high resolution. These observations revealed sigmoids have very complex structures.
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The Anatomy of a Solar Explosion in 3-D

Nancy Atkinson — Wed, 15 Apr 2009 01:27:43 +0000

Wouldn't it be great if solar physicists could predict sun storms just like meteorologist predict hurricanes? Well, now perhaps they can. NASA’s twin STEREO observatories have made the first 3-D measurements of solar explosions, known as coronal mass ejections (CMEs), allowing scientists to see their size and shape, and image them as they travel approximately 93 million miles from the sun to Earth. With STEREO, scientists can now capture images of solar storms and make real-time measurements of their magnetic fields, much the same way that satellites allow forecasters to see the development of a hurricane. Eruptions from the sun’s outer atmosphere, or corona, can wreak havoc on satellites (and astronauts) in orbit or induce large currents in power grids on Earth, which can cause power disruptions or black outs.

"We can now see a CME from the time it leaves the solar surface until it reaches Earth, and we can reconstruct the event in 3D directly from the images," said Angelos Vourlidas, a solar physicist at the Naval Research Laboratory, Washington, and project scientist for the Sun Earth Connection Coronal and Heliospheric Investigation aboard STEREO. In the video above, see some of the 3-D imagery, and hear Vourlidas talk about about the new findings.
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Where Are All the Sunspots?

Nancy Atkinson — Thu, 02 Apr 2009 16:56:18 +0000

There's not a lot happening on the sun these days, at least in the sunspot department. "We're experiencing a very deep solar minimum," says solar physicist Dean Pesnell of NASA’s Goddard Space Flight Center in Greenbelt, Md. In 2008, no sunspots were observed on 266 of the year's 366 days (73 percent). Sunspot counts for 2009 have dropped even lower, percentage-wise. As of March 31st, there were no sunspots on 78 of the year's 90 days (87 percent). Those who keep an eye on the sun say this is the quietest sun in almost a century. So, what does this all mean?
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Sounds Painful: Are Deadly Asteroids Stuck in Earth's Lagrangian Points?

Ian O'Neill — Sat, 21 Feb 2009 10:12:38 +0000

Did the asteroid that hit the Earth, creating the Moon, originate from one of Earth's Lagrangian points? (ESA)

Two solar telescopes launched to study coronal mass ejections and the solar wind have been sent to do an entirely different task. Currently, the Solar Terrestrial Relations Observatory (STEREO) probes are flying in opposite directions; one directly in front of Earth's orbit and the other directly behind. This unique observatory is intended to view the solar-terrestrial environment in unprecedented detail, allowing us to see the Sun from two vantage points.

This might sound like an exciting mission; after all, how many space-based observatories have such a unique perspective on the Solar System from 1 AU? However, both STEREO probes are currently moving further away from the Earth (in opposite directions), approaching a gravitational no-man's land. STEREO is about to enter the Earth-Sun Lagrangian points L₄ and L₅ to hunt for some sinister lumps of rock…
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The Neutral Hydrogen Gun: A New Solar Flare Phenomenon

Ian O'Neill — Tue, 16 Dec 2008 02:21:43 +0000

The X9 flare as seen by the Solar X-Ray Imager on NOAAs GOES-13 satellite (NASA)

In 2006, one of the largest solar flares observed for 30 years erupted, saturating X-ray cameras on board observatories orbiting Earth. The December 5th event was a powerful X-ray flare, registering "X9" on the scale of powerful "X-class" flares. Even though flares weighing in at X20+ have been observed, the X9 is a rare event all the same. However, this 2006 flare is fast becoming known not only for its energetic characteristics. Shortly after the flare, solar astronomers expected to see a flood of interplanetary ions being ejected by the Sun. However, they detected something else; not only a particle they weren't expecting, but a particle that shouldn't be there…
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Asteroseismology: Observing Stars Vibrate with CoRoT

Ian O'Neill — Thu, 23 Oct 2008 22:36:45 +0000

Observing a stars brightness pulsate may reveal its internal structure say researchers using the Convection Rotation and Planetary Transits (CoRoT) observatory. The highly sensitive orbital telescope can detect tiny variations in a distant star's brightness, leading astronomers into a new field of stellar seismology called "asteroseismology."

Seismology is more commonly used by scientists on Earth to see how waves travel through the terrestrial crust, thereby revealing the structure of the material below us. Even solar physicists use the method of helioseismology to understand the interior of our Sun by observing its wobble. Now, by observing the slight changes in stellar brightness, it is possible to remotely probe deep into the inner workings of a distant star…
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Podcast: The Life of the Sun

Astronomy Cast — Mon, 06 Oct 2008 17:26:35 +0000

We've talked about the Sun before, but this time we're going to look at the entire life cycle of the Sun, and all the stages it's going to go through: solar nebula, protostar, main sequence, red giant, white dwarf, and more. Want to know what the future holds for the Sun, get ready for the grim details.

Click here to download the episode.

Or subscribe to: astronomycast.com/podcast.xml with your podcatching software.

The Life of the Sun – Transcript and show notes.

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Solar System's Protective Shield is Weakening; Solar Wind Velocity at Record Low

Ian O'Neill — Thu, 25 Sep 2008 15:56:52 +0000

Solar wind output is at its lowest since accurate records began 50 years ago. This finding comes from the seasoned ESA/NASA solar probe Ulysses, which completed nearly three polar orbits of the Sun from 1993 to 2008 (it is still functioning today, but at a reduced capacity). Although a weakening of the solar wind may not sound very important, the effects of this reduction will have serious implications, diminishing the natural defences of the heliopause (our Solar System's invisible barrier) which protects us from high energy cosmic rays blasting through intergalactic space…
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Solar Cycle 24 Sunspots Finally Say "Hello!"

Ian O'Neill — Tue, 23 Sep 2008 01:11:49 +0000

After an extended period of calm for Solar Cycle 24, a cluster of sunspots have appeared on the disk of the Sun. Although we have observed sunspots since the beginning of this new solar cycle (which officially began on January 4th, 2008 with the observation of a high-latitude sunspot pair), this is the first time for many months "new" Cycle 24 sunspots have shown themselves. Before today, the sunspots (including occasional flares and coronal mass ejections) belonged to the previous cycle (Cycle 23). It would appear the spots have evolved into a cluster in a high-latitude location with the magnetic polarity consistent with this new cycle. But does this mean we can expect an increase in solar activity after this pretty dull period of "blank" solar disk observations? Your guess is as good as mine…
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"Eight Minutes of Terror": Solar Physicists Find a Supersonic Way to See the Transition Region

Ian O'Neill — Sat, 06 Sep 2008 07:30:23 +0000

Solar physicists will have the unprecedented opportunity to peer inside one of the most mysterious regions in the Sun's atmosphere. Separating the chromosphere (at a temperature of a few thousand Kelvin) and the extended corona (at a temperature of over a million Kelvin) is a very thin layer about 5000 km above the photosphere (a.k.a. the Sun's "surface"). The transition region dictates the characteristics of the hot plasma passing from the Sun into space and is right at the start of the solar-terrestrial chain, controlling space weather. We are unable to directly observe the transition region as it doesn't radiate in wavelengths observable from the Earth's surface, but it does emit UV radiation observable from space. So a group of solar researchers are packing some very sensitive instrumentation into a sounding rocket that will very briefly take some snapshots of the transition region. But they will have to be quick, from instrument deployment to re-entry, only eight minutes will be allowed to take the necessary UV spectroscopic observations…
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Sunspot Pair Observed Today – Is Solar Cycle 24 Waking Up?

Ian O'Neill — Thu, 21 Aug 2008 21:52:25 +0000

Amateur astronomers have observed the first sunspots to appear on the solar surface for weeks. This period of extreme magnetic calm has made some scientists believe that Solar Cycle 23 might be a quiet affair. This comes in stark contrast to NASA's 2006 forecast that this cycle would be a "doozy." Whether or not the slow start of solar activity is indicative of things to come, we're not sure, but it sure is great to see activity starting to churn on the solar surface once more…
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Ten Mysteries of the Solar System

Ian O'Neill — Mon, 18 Aug 2008 23:42:14 +0000

We've all wondered at some point or another what mysteries our Solar System holds. After all, the eight planets (plus Pluto and all those other dwarf planets) orbit within a very small volume of the heliosphere (the volume of space dominated by the influence of the Sun), what's going on in the rest of the volume we call our home? As we push more robots into space, improve our observational capabilities and begin to experience space for ourselves, we learn more and more about the nature of where we come from and how the planets have evolved. But even with our advancing knowledge, we would be naive to think we have all the answers, so much still needs to be uncovered. So, from a personal point of view, what would I consider to be the greatest mysteries within our Solar System? Well, I'm going to tell you my top ten favourites of some more perplexing conundrums our Solar System has thrown at us. So, to get the ball rolling, I'll start in the middle, with the Sun. (None of the following can be explained by dark matter, in case you were wondering… actually it might, but only a little…)
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STEREO Maps Far Reaches of Solar System

Nancy Atkinson — Wed, 02 Jul 2008 17:36:59 +0000

NASA's twin STEREO spacecraft have been studying the sun since their launch in 2006. But the mission made a surprising and unexpected discovery by detecting particles from the edge of the solar system, and for the first time, scientists have now been able to map the region where the hot solar wind meets up with the cold interstellar medium. However, this wasn't done with optical instruments imaging in visible light, but by mapping the region by means of neutral, or uncharged, atoms. This breakthrough is a "new kind of astronomy using neutral atoms," said Robert Lin, from the University of California Berkeley, and lead for the suprathermal electron sensor aboard STEREO. "You can't get a global picture of this region, one of the last unexplored regions of the heliosphere, any other way because it is too tenuous to be seen by normal optical telescopes." The findings also help clear up a discrepancy in the amount of energy in the region found by the Voyager 2 spacecraft as it passed through the edge of the solar system last year.
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