![]() ![]() "Because they contain little solar material, they have lower temperatures and thus appear much darker than their surroundings. "Coronal holes are low-density regions of the sun's atmosphere, known as the corona," says NASA. One of the lesser-known weather phenomena on the sun's surface are coronal holes, like the massive one that was recently captured by NASA's Solar Dynamics Observatory (SDO) and featured this week in a short video from the space agency. “I want to see how the corona changes.While you might think the sun has pretty much just one weather pattern – blistering and violent with a chance of radiation poisoning – it can actually be quite varied. “This is pure science that can be done only during an eclipse,” Yanamandra-Fisher says. And Yanamandra-Fisher’s group might be the first to collect data from the same point on Earth. There is plenty of room for new observations to help decipher the corona’s mysteries. That allows streamers to spread toward the poles and occupy new space.Īlthough physicists have been studying the corona’s changes for 150 years, that’s still only a dozen or so solar cycles’ worth of data. The sun’s equatorial magnetic field also splits to straddle the equator rather than encircle it. Scientists suspect that’s because as the sun ramps up its activity, its strengthening magnetic field lets the streamers stretch farther out into space. During high activity, they can get more stringy and spread out. During low activity, they tend to be more squat and concentrated closer to the sun’s equator. Observations of the corona during eclipses going back as far as 1867 suggest that streamers vary with solar activity. Sun corona hole 2016 series#Citizen CATE will place 68 identical telescopes along the eclipse’s path from Oregon to South Carolina.Īs part of a series of experiments, Yanamandra-Fisher and her colleagues will measure the number, distribution and extent of streamers in the corona. This year, she’s teaming up with a crowdsourced eclipse project called the Citizen Continental-America Telescope Eclipse experiment. Yanamandra-Fisher will be in Carbondale for both events. But seven years from now during the 2024 eclipse, it will be on the upswing again, nearing its next peak. 21 solar eclipse, solar activity will still be on the decline. Even at the most recent peak in 2014, the sun’s number of flares and sunspots was pathetically wimpy ( SN: 11/2/13, p. Right now, the sun is in a period of exceptionally low activity. So solar eclipses are the only time researchers can get a detailed view of what the inner corona, where the streamers are rooted, is up to. Even space telescopes that are trained on the sun can’t see the inner part of the corona - they have to block some of it out for their own safety ( SN Online: 8/11/17). The corona is normally invisible from Earth, because the bright solar disk washes it out. Images show the sun’s face changing from being nearly clear in 2010 to being dotted with maximum sunspots and bright flares as the cycle peaked in April 2014, and then clearing up again. UPS AND DOWNS NASA’s Solar Dynamics Observatory has been watching the sun for most of a solar cycle. ![]()
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