NASA images shed light on the sun
Professor Robert W. Walsh is on the Rock with his exhibit ‘From the Earth to the Sun’, which shows images of the Earth’s closest star in an array of colours captured by the NASA’s Solar Dynamic Observatory.
The NASA Solar Dynamic Observatory is a satellite that orbits the earth and stares at the sun continuously, taking an image every 10 seconds of different parts of the sun’s electromagnetic spectrum.
“It monitors the sun on our behalf,” said Professor Walsh who works at the University of Central Lancashire and where the data from the NASA Solar Dynamic Observatory is analysed.
“We use the data to try and understand the physics of the star and therefore we are using this as an exhibition to show what the sun is really like,” said Professor Walsh.
“Sometimes we look at the sun as a featureless ball in the sky that provides light, heat and energy but if you look at this exhibit you will see that the sun has quite intricate, dynamic and is a beautiful object,” he added.
His exhibition shows the colours of the sun that humans cannot see as it is in waves of light that our eyes are not tuned to.
“The sun radiates in all colours, in all wavelengths, our eyes are tuned to white light. What we did here is take parts of the spectrum that our eyes aren’t tuned to, particularly extreme ultraviolet light which you can only see by going out of the Earth’s atmosphere,” he said.
“We capture that with special filters that actually allow you to capture that part of the spectrum and when you have that we actually paint them, so that when I see this [image] I know which wavelength we have used,” he added.
The red one for example shows the extreme ultraviolet light emitted by the element Helium, which has a wavelength of 30.4 nanometres and a temperature of 50,000 Kelvin.
“The yellow ones is actually iron, the metal in Earth it’s an electrified gas [plasma] in the atmosphere of the star and that radiates at about one to two million degrees. The sun is a very ordinary star and we do not understand the one closest to us how are we going to understand stars elsewhere,” said Professor Walsh.
He believes his exhibition is an interesting way to show schoolchildren and adults alike that the sun is actually very interesting and dynamic.
This is the first time the exhibition will be held outside of the U.K. When touring the U.K. with it he found that “people just stand and look at it, wonder at the fact this isn’t some computer generated cartoon this really is what the sun looks like,” he said.
The reason Professor Walsh is on the Rock is down to a lecturer in Computer Science at UCLA N and local Nicky Danino. She also is one of the senior members who look after students in the school of Physical Sciences.
“She asked us as astronomers if we had anything we could bring it here, and as we had been touring the UK with it, we decided to bring it here,” he said.
Professor Walsh will be at Europa Point tomorrow evening to give a talk and assist people in observing planets and galaxies through dedicated telescope viewings.
Sun myths busted
Is it a big ball of fire?
“Not really fire,” Professor Walsh answers. “It is burning fuel at the heart of the star, that’s hydrogen, it’s a huge naturally occurring nuclear reactor and it is burning and using up its fuel at the centre of the star.”
“Then that energy leaks out through the various layers and comes to the surface and down to us here on earth.”
“That takes millions of years, the energy released at the centre of the sun does not actually reach us till millions of years later,” he added. This is because of how the energy travels inside the star.
Therefore, “it is not really flames but more like a chemical reaction although no chemical reactions are taking place. There is a heck of a load of energy that is being released and we only get a very tiny percent of that here on Earth, to give us the heat and light we need for life on this planet,” he said.
Will the sun suddenly explode in a big supernova?
“We do not believe that is going to happen with the sun. We see that in other stars but you have to have a certain size and mass of star for it to do that,” he answered.
“For the sun, it is sort of going through a bit of a midlife crisis, it’s about halfway through its life at four and a half billion years old and another four and a half billion year to go. What will happen is that fuel inside will burn up and it cannot hold the gravity and hold it together so it will start to expand.”
“That will form a red giant which will probably envelop the Earth.”
“It will start to contract back down again, form a white dwarf and really shine no more.”
“But, that is about another four and a half billions years away,” he added.
Pics by Johnny Bugeja and NASA