By Jonny Lupsha, Wondrium Staff Writer
NASA and the European Space Agency published the closest-ever photos of the Sun, according to NASA. The unmanned spacecraft Solar Orbiter was launched in February. Due to the pandemic, the mission control team worked remotely from home, for the first time, to perform critical operations. The Sun is the best star for us to study.
NASA’s partnership with the European Space Agency (ESA) provided us with some very exciting pictures last week. “The first images from ESA/NASA’s Solar Orbiter are now available to the public, including the closest pictures ever taken,” an announcement on NASA’s website said. “Solar Orbiter is an international collaboration between the European Space Agency, or ESA, and NASA, to study our closest star, the Sun. Launched on Feb. 9, 2020 (EST), the spacecraft completed its first close pass of the Sun in mid-June.”
NASA scientists believe the pictures will help humankind understand the Sun’s atmospheric layers, which in turn will give us information about how the Sun drives space weather near the Earth. Since the Sun is the nearest star to us, it’s our best opportunity for studying stars.
Contents of a Star
Most of us learned in school that stars are enormous balls of burning gases. While that’s true, science has allowed us to get more specific with regard to the solar features of the Sun.
“The Sun is mostly hydrogen: For every million atoms of hydrogen, there’s about 85,000 atoms of helium, 850 atoms of oxygen, 400 atoms of carbon, 120 of neon, 100 of nitrogen, and 47 of iron,” said Dr. Alex Filippenko, Professor of Astronomy and the Richard and Rhoda Goldman Distinguished Professor in the Physical Sciences at the University of California, Berkeley. “The other elements are just sort of trace elements in the Sun.”
With this atomic make-up of the Sun, we get a fair picture of the make-up of the universe itself. On the other hand, Dr. Filippenko said, on Earth we have ample amounts of silicon, oxygen, carbon, and other atoms, which aren’t exactly representative of their abundance throughout the universe.
“By mass, the Sun is 73% hydrogen, 25% helium, and only 2% consists of elements that are heavier than helium,” he said.
It’s no wonder we want to study the Sun for a better understanding of the universe itself.
Journey to the Center of the Solar System
NASA said that the Solar Orbiter pictures will help us understand the Sun’s atmospheric layers. What does that mean?
“If you look at a cross-section of the Sun, it has a very hot core—about 15 million degrees on the absolute Kelvin temperature scale,” Dr. Filippenko said. “That’s where the nuclear reactions generate the energy that comes out of the Sun. Surrounding the core are two zones: the radiative zone and the convective zone.”
Dr. Filippenko said these two zones describe how the energy from the nuclear reactions get out from the core of the Sun.
One way in which that happens—specifically traveling from the core to the radiative zone—is radiation, like the heat from a candle raising the temperature of a thermometer. However, the Sun is so dense that the energy bounces around to get from one point to the other rather than travel in a straight line. The end result is radiative diffusion. That leaves the convective zone.
“Convection is the process by which you heat a bubble of gas or liquid, and it expands and becomes less dense and more buoyant,” Dr. Filippenko said. “That causes it to rise, and it can deposit its heat to the surroundings higher up. That makes it cooler and more dense, which makes it come back down again.”
From there, the cycle repeats, like boiling water in a pot. In this case, the Sun is the pot and the burning gas is the water.
Fittingly enough, we know that convection takes place because of hot pockets of gas that bubble up to the surface—which we’ve seen thanks to satellite images taken by spacecraft just like Solar Orbiter. There’s no telling what its new images will tell us.
Dr. Alex Filippenko contributed to this article. Dr. Filippenko is Professor of Astronomy and the Richard and Rhoda Goldman Distinguished Professor in the Physical Sciences at the University of California, Berkeley. He earned his BA in Physics from the University of California, Santa Barbara, and his PhD in Astronomy from the California Institute of Technology.