Most of the potentially habitable exoplanets we’ve discovered orbit small red dwarf stars. Red dwarfs make up about 75% of the stars in our galaxy. Only about 7.5% of stars are g-type like our Sun. As we look for life on other worlds, red dwarfs would seem to be their most likely home. But red dwarfs pose a serious problem for habitable worlds.Continue reading “Even older red dwarf stars are pumping out a surprising amount of deadly radiation at their planets”
Star’s can be full of surprises; some of them nasty. While our own Sun appears pretty placid, science has shown us that’s not the case. Coronal mass ejections and solar flares are the Sun’s angry side.
And the Sun has only a mild case of the flares, compared to some other stars.Continue reading “Just How Bad are Superflares to a Planet’s Habitability?”
That’s one big, black blemish on the Sun today! Rarely have we been witness to such an enormous sunspot. Lifting the #14 welder’s glass to my eyes this morning I about jumped back and bumped into the garage.
Properly shielded, it was very easy to see with the naked eye. Unlike some other naked eye sunspots, this one showed structure. The eastern end was darker, the western half grayer and more extended.
Watch the giant spot rotate into view and grow right before your eyes in this 72-hour time-lapse video taken by SOHO’s HMI imager Oct. 18-20, 2014
Through a small telescope, the mix of dark umbras scattered amid weirdly sculpted penumbral “islands” was incredible to see. Photographs like the one above are wonderful documents, but witnessing this beautiful complex magnetic mess with your own eyes is another experience altogether. Region 2192 continues to grow and size and complexity and is now the largest sunspot group of solar cycle 24 which began in 2009 – more than five years ago!
Every sunspot marks a region on the Sun’s shiny outer skin called the photosphere where magnetic energy is concentrated. Strong magnetic fields within a sunspot group quell the turbulent churning of the photosphere, chilling the region by several thousand degrees. Sunspots appear dark against the Sun’s blazing disk because they’re cooler. Cooler meaning 8,000 F instead of 11,000 F, so yes, they’re still VERY hot.
Watch as Region 2192 crackles with energy and flares as seen in far ultraviolet light with NASA’s Solar Dynamics Observatory.
Energy stored in sunspots’ twisted magnetic fields can suddenly be released in violent, explosions called solar flares. Billions of tons of solar plasma – the sizzling mix of protons and electrons that composes the Sun – are heated to millions of degrees during the explosion and rapidly accelerated into space. Radiation from radio waves to X-rays and gamma rays fans out at the speed of light. Fortunately for us, our atmosphere and planetary magnetic field protect us from most of what flares can fling our way.
But as the Sun rotates this monster into our line of sight, possibilities for Earth-directed flares and coronal mass ejections increase as do geomagnetic storms, the bringer of auroras. Already in the past 48 hours, the spot has dished out seven M-class flares and a powerful X-1 flare even before it has fully come into view. There’s more to come – Region 2192 harbors an unstable beta-gamma-delta magnetic field ripe for additional flaring including more of the X-class variety.
There’s no doubt now that this behemoth will stick around to add a whole new dimension to tomorrow’s partial solar eclipse. I can’t wait to see the Moon’s black curve approach and at least partially occult the group from view. If you’re interested in getting some one-of-a-kind pictures of the scene, please see our own Dave Dickinson’s excellent guide on photographing the partial eclipse.
While we’re on the Moon, early morning risers had the pleasure of its company just one day before New Moon and solar eclipse. I was out watching the Orionid meteor shower. While not rich like the Perseids or Geminids I managed to catch a few including a few lucky shots with the camera.
The shower has peaked but will still be active the remainder of the week if you’re inclined to take a look. And I can’t resist. How about one last sweet close-up photo of sunspot group 2192? I have a feeling you won’t mind.
Remember yesterday when we mentioned two X-class flares erupting from the Sun within the space of about an hour? We probably should have waited a bit and gone for the trifecta: this morning the same active region flared yet again, making it three high-powered flares within a single 24-hour period.
(And to think this active region has only just come around the corner!)
On June 10, 2014, AR2087 announced its arrival around the southwestern limb of the Sun with an X2.2 flare at 11:41 UT (7:41 a.m. EDT). Then, just over an hour later, another eruption: an X1.5 flare at 12:55 UT. This got pretty much everyone’s attention… here comes 2087!
Perhaps figuring third time’s a charm, the active region blazed with a third flare this morning at 9:05 UT (5:05 a.m. EDT). “Only” an X1-class, it was the weakest of the three but AR2087 still has plenty of time for more as it makes its way around the Sun’s face — all the while aiming more and more our way, too.
Here’s a video of SDO observations showing the two June 10 flares:
X-class flares are the strongest in the letter-classification of solar flares, which send blasts of electromagnetic energy out into the Solar System. While these most recent three are low on the X-scale, they may result in increased auroral activity — especially since it appears that the first two were followed by a pair of CMEs that “cannibalized” each other on their way out. The resulting merged cloud of charged particles is expected to nick Earth’s magnetic field on Friday, June 13. (Source: Spaceweather.com)
No CME has been observed from the June 11 flare, but again: AR2087 hasn’t left the stage yet. Stay tuned!
As an amateur astronomer, two of the most frequently questions I’m asked are “When is the best time to see the aurora borealis and where is the best place?” In terms of place, two locations comes to mind: Churchill, Manitoba and Tromso, Norway. But until such time as the transporter is invented, most of us will be staying closer to home. The simple answer is north and the farther north the better.
As for the time, in the northern border states of the US, auroras occur fairly regularly around the time of solar maximum, when the sun peaks in storm activity. The current solar cycle tops out this summer and fall, so your chances at seeing northern lights are far better now than a year and a half ago when solar activity saw a steep decline during a protracted minimum.
Even though the CME unleashed by active region 1429 initially hit Earth a bit softer than expected yesterday (read why here), it ended up gaining some extra “oomph” once the magnetic fields lined up right… enough to ignite some amazing displays of aurorae like the one shown above over Iceland, photographed by Jónína Óskarsdóttir!
And that wasn’t the last we’d hear from AR1429 either; at around 10:30 pm EST on March 8, the region lit up again with an M6.3 flare… although smaller than the previous X5.4-class flare, it produced a temporary radio blackout and released another Earth-directed CME, which is expected to arrive in the coming hours.
Dr. Alex Young, solar physicist at NASA’s Goddard Space Flight Center, reported this morning on his blog The Sun Today:
The flare produced a temporary radio blackout as well as a possible Earth directed CME. We will have to wait and see. The sunspot group still shows potential for more activity as the region sits near the central meridian of the Sun. Facing directly at Earth this is a prime location to produce more geo-effective solar activity.
Here is a look at the flare captured by the 131 Angstrom wavelength camera on the Solar Dynamics Observatory (SDO). This shows us the super hot 5-10 million degree plasma produced by the solar flare.
Dr. Young also noted that bright aurorae could be visible in lower latitudes as a result of the latest CME, expected to impact Earth at 1:50 am EST:
Aurora watchers at higher latitudes such as the northern US should keep their eyes out in the early morning and maybe even into tonight depending upon how this storm progresses.
Many times the size of Earth, active region 1429 has been the source of at least five significant flares over the past week. As it moves across the face of the Sun, its shape has become more and more complex — a sure sign, notes Dr. Young, that magnetic forces within it are twisting further and further towards a breaking point. And when they snap, there’s a flare.
“It’s interesting, they kind of look like a mole,” Dr. Young said during an interview on March 8. “And when you monitor a mole, they tell you as long as it stays in a nice symmetric shape and it doesn’t become really complicated and complex, it’s okay. It’s the same sort of thing with sunspots… when they become complicated and twisted, then that mean the magnetic fields inside of them have become more twisted, like a rubber band twisting around until little knots pop up in it. And right now we have been monitoring that sunspot and it is getting more complex.”
As far as the effects we see here on Earth are concerned, that’s all about the resulting CME — the enormous cloud of charged solar particles that gets blown out into the Solar System. If that cloud impacts Earth’s magnetic field, and if the direction of the cloud happens to be opposite the direction that Earth’s magnetic field is pointed, a lot of energy is “pumped into” our magnetosphere, resulting in a geomagnetic storm.
During yesterday’s CME impact the Earth’s magnetic field was pointed north — the same direction as the CME. As a result much of the solar material simply flowed along and over it. But the wake ended up getting caught up in the south-directed part of the field, ramping up the energy index (measured as Kp) as the hours progressed. As yet there’s no way to know for certain how a particular CME will align with Earth’s magnetic field.
According to physicist Dr. Philip Scherrer of Stanford University, “we still need better — or perhaps faster — models” to be able to accurately predict the orientation of incoming CMEs. “We are perhaps a few years of research away from completing the picture.”
Currently the geomagnetic storm level is at G3, which according to the NOAA’s Space Weather Scale could result in voltage problems on power systems, increased drag on satellites and “intermittent satellite navigation and low-frequency radio navigation problems… and aurora has been seen as low as Illinois and Oregon.”
So keep an eye out for northern lights in tonight’s skies, and stay tuned for more updates!
Thanks to Dr. Alex Young for the information! You can follow him on Facebook and Twitter and on his personal blog The Sun Today. Also thanks to Dr. Phil Scherrer at Stanford University and SpaceWeather.com for the heads-up on Jónína’s photo. See more of her aurora photography here. (Used with permission.)
The Crab Nebula is one of the most popular targets for astronomers of all stripes. It is readily viewable in moderate sized amateur telescopes and wows new viewers at star parties when they’re informed they’re looking at the remnant of a supernova that exploded in 1054 AD. The nebula is also a popular target for professional astronomers looking to study physics in the environment of a pulsar. Powered by synchrotron radiation from the pulsar, the nebula glows brightly across numerous wavelengths in a steady manner that is so consistent, that astronomers have used it to calibrate instruments in different portions of the spectrum. The largest regular variation discovered was a mere 3.5% in the X-ray portion of the spectrum.
But on September 22 of 2010, the Italian Space Agency’s AGILE satellite observed a sudden brightening in the nebula in the gamma ray portion of the spectrum. The Large Area Telescope (LAT) on board the Fermi Gamma-Ray Space Telescope, which observes the Crab regularly, confirmed this flaring. Strangely, telescopes observing the nebula in other spectral regimes showed no brightening at all. The lone exception was a small knot roughly one arcsecond in diameter seen by the Chandra X-ray telescope which is believed to correspond to the base of a jet emanating from the pulsar.
Many telescopes observed the central pulsar in X-rays as well as radio to attempt to discover if there had been a sudden change in the power source itself that caused the sudden brightening, but no changes were apparent. This suggests that the flare didn’t come directly from the pulsar, but rather from the nebula itself, perhaps as an interaction between the jet and the magnetic field of the nebula causing intense synchrotron radiation. If this is the cause, then the energy of the accelerated electrons is among the highest of any astronomical event. Such a case is of interest to astronomers and physicists because it provides a rare test bed into relativistic physics and particle acceleration theory.
While this event was certainly noteworthy, it was not entirely unique. AGILE detected a previous flare on October 7, 2007 and Fermi’s LAT had discovered another in February 2009. Currently, none of these events have been entirely explained but will likely give astronomers a target for future studies. Based on the amount of coverage the Crab Nebula receives from telescopes, astronomers are no expecting that such flares are a relatively common occurrence, happening about once a year. If so, this will provide an excellent opportunity to study such events with more scrutiny.