Nothing short of amazing. Check out this news video created from images taken by the Daniel K. Inouye Solar Telescope, located on the summit of Mt. Haleakala on the island of Maui in Hawaii. The images, just released, are the highest resolution ever of the sun’s surface called the photosphere. That’s the shiny face of the sun, the part that illuminates the Earth.
The cell-like structures are called granules. Each spans the size of the state of Texas or about 800 miles (1,290 km) across. It would take a little more than 13 hours to drive across a granule if you could had a car with an excellent air conditioner and really good tires. Granules are also visible in a properly filtered 3-inch or larger telescope. Granulation gives the sun a fine-grained texture similar to a grainy photograph. The photos and video reveal features as small as 18 miles (30 km) which is frankly amazing considering that the sun is 93 million miles (150 million km) away.
Granules are how the sun transports heat from its interior to the surface. Hot solar material called plasma (a mix of protons and electrons) rises in the bright centers of “cells,” cools off and then sinks below the surface in the dark lanes between the cells in a process known as convection. In these dark lanes we can also see the tiny, bright markers of magnetic fields. The bright specks are thought to channel energy up into the outer layers of the solar atmosphere called the corona and may be the reason the corona’s temperature is more than a million degrees.
Astronomers have long sought to understand why the corona is so blasted hot compared to the sun’s photosphere, which registers a more refreshing 10,800° F (6,000° C).
The Daniel K. Inouye Solar Telescope, operated by the National Science Foundation, is the largest solar telescope in the world with a 4-meter-wide (157.5 inches) mirror. Its mission is to advance our understanding of the Sun, both as a star and in how it affects the Earth. These are just the first images so we can only imagine what’s to come.
Located at 10,000 feet altitude in a region with low air turbulence the telescope can discern details as small as 0.1 arc-second, equal to 1/18,000th the apparent diameter of the full moon, and also observe the sun’s inner corona. The sun is all about magnetic fields — much like the magnetic field around an ordinary bar magnet. Scientists want to study them at the finest level of detail possible to see how small fields bubbling up from the surface help create and sustain the sun’s magnetism and it up-and-down cycles of solar activity.
The planning for the observatory began nearly 30 years ago, and astronomers expect to operate the telescope for at least 44 years, the equivalent of four solar cycles. Next time you’re on vacation in Maui look southwest from the Summit parking lot, and you’ll see the dome nestled amongst several others.
We’re lasering in on the sun the past fews days because of several near-simultaneous solar “missions” that are now or soon will be underway. We’ve already touched on NASA’s speed-demon Parker Solar Probe and its daring sunward dive to study solar particles and magnetic fields on-site. A brand new 7-year solar mission is set to launch on Friday, Feb. 7. Called Solar Orbiter, it’s a collaboration between NASA and the European Space Agency (ESA).
Like Parker, Solar Orbiter will study the stream of particles flowing from the sun called the solar wind. But unlike that mission its focus will be on the sun’s polar regions. Until now, they’ve been inaccessible because Earth orbits in the plane of the sun. When you’re stuck in the plane, you can’t see above or below the sun to see what’s happening on its top and bottom.
Scientists will modify the Orbiter’s orbit by slingshotting it past the Earth and Venus, using their gravities to bump it into an orbit that’s tilted 24°. From this perch, we can look both under and over the sun. With the new telescope in operation and two solar missions underway, we’re about to begin a solar renaissance. Humanity has never been hotter to know more about the sun.
A final note: I want to invite you to listen to Tim Robertson’s podcast released Feb. 1 called the Observers Notebook — Betelgeuse with Bob King. Tim creates the official podcast for the American Lunar and Planetary Observers (ALPO). We had a lot of fun talking about this amazing star. Come join us — just click the link to listen. Thanks!