Category Archives: sun
On May 9, 2016, over the course of seven and a half hours beginning at 7:12 a.m. EDT (11:12 UTC) Mercury passed across the disk of the Sun, appearing to observers on Earth as a small dark dot in front of the massive brilliance of our home star. While the event wasn’t visible to the naked eye (the Sun is just too bright and Mercury just too small) those with filtered telescopes and solar projection devices (like what I had set up) were able to see Mercury silhouetted against the Sun, and that most certainly included solar photography master Alan Friedman who captured the amazing image above from his home in Buffalo, NY.
It hasn’t even been found yet (they’re still working on that) but the recently-announced Planet Nine is already spurring discussion amongst the world’s astronomers. One of the recent topics surrounding this alleged new planet is (again, besides where it’s hiding) how it formed and how it got into the incredibly distant orbit it’s thought to be in. Estimated to be nearly as massive as Neptune, and possibly similarly gaseous as well, Planet Nine would be an anomaly among the small frozen balls of ice that typically haunt the outer Solar System. Recently, a team of scientists decided to investigate the possibility that Planet Nine did not originate in our Solar System at all but rather was captured from another star, back when the Sun’s stellar family was much closer together… and apparently much more trusting. (That’ll teach ’em.)
I love models that demonstrate the incredible size and space of the Solar System, very much so because many illustrations and diagrams fail to portray it accurately (and for very good reason…it’s enormous.) The most recent is shown here, enthusiastically created and narrated by former NASA engineer Mark Rober. This particular demonstration is unique in that it’s the only one (that I’ve seen so far) that includes the newest possible-planet in the Solar System, “Planet Nine,” a Neptune-mass world that may orbit the Sun up to four times farther away than Pluto. Check it out above, and you can find some other cool scale models of the Solar System I’ve encountered previously below.
(And remember kids, space is really, really, really BIG.)
Happy Launchiversary SDO! NASA’s Solar Dynamics Observatory lifted off aboard an Atlas V rocket from Cape Canaveral on Feb. 11, 2010, and has been observing our home star in high-definition ever since. SDO has provided us with unprecedented views of the Sun’s ever-changing atmosphere and data on the space weather it creates over the course of its prime mission and, now in an extended mission, will hopefully continue to do so for many years to come.
The video above is a compilation of images SDO acquired with its Atmospheric Imaging Assembly (AIA) instrument during 2015, made into a single time-lapse video. Each frame is 2 hours of real time and clearly shows the Sun’s constant magnetic activity and movement of its 25-day-long rotation.
Short blank gaps and shifts in movement are due to SDO going offline occasionally for recalibration and repositioning itself in Earth orbit (and sometimes the Moon and Earth even get in the way briefly!) At 2:50 a solar physicist from Goddard Space Flight Center describes some of the features seen in the video, so be sure to watch the whole thing. (You can find an even higher-resolution version here.)
Learn more about SDO and see its most recent images here.
Our Sun may be made up of 98% hydrogen and helium but the remaining two percent comprises many other elements, detectable by their unique absorption lines within the gamut of white light we receive on Earth. One of those elements is calcium, which exists in ionized form in relatively tiny amounts in the Sun’s chromosphere – but still enough to allow images to be made using special filters aligned to the wavelength of its absorption line. And this is precisely what photographer Alan Friedman did on April 12, 2015 when he captured the image above!
Many of the features seen on the Sun might look like tongues of flame or fiery eruptions, but there’s no fire or lava on the Sun – its energetic outbursts are driven by powerful magnetic fields that rise up from its internal regions and twist, loop, and coil far out into space.
In addition to these far-reaching lines there is a network of magnetic fields that cover the Sun’s “surface” (that is, its photosphere) like a web – a web outlined by the edges of large-scale features called supergranules. Created by rising zones of hot solar material, these 35,000km-wide “bubbles” on the photosphere carry bundles of magnetic regions to their edges, fueling the network.
What one team of researchers has now found , through long-term observations with the Hinode satellite, is that the supergranules are able to replenish the entire magnetic surface web in a surprisingly short time – only 24 hours.