To celebrate a decade of operations of the Solar Dynamics Observatory (SDO), NASA released an epic 10-year time-lapse of the Sun, giving us a view of the star that we otherwise don’t get to see because of its sheer brightness.
The time-lapse, which has a fitting background score titled Solar Observer, is a 61-minute video where each second represents a day from June 2, 2010 to June 1, 2020. Each day is compiled from one photo every hour, bringing the total number of photos to about 87,500.
If watching the whole thing is a bit of a stretch, you can instead watch the 1-minute version in NASA’s tweet below.
The video shows all the fiery adventures of the Sun in its 11-year solar cycle, but there are some moments where it goes dark. This is when the Earth or moon gets in between the SDO and the Sun, or when the cameras go offline for a week in 2016 due to a technical glitch. Barring these brief moments, the SDO has captured all of the Sun’s intense plasma waves, fantastic flares, mysterious magnetic spots, and massive solar tornadoes.
The SDO has also captured some historical moments. One such incident took place on 5 June 2012 when Venus passed in front of the Sun. This is set to happen again only in 2117!
So, how did NASA make this incredible time-lapse? Let’s start with the SDO.
What is the Solar Dynamics Observatory?
Although the Sun is our closest star, a lot about it is still unknown. The SDO is a NASA mission that aims to narrow this knowledge gap.
Since its launch in February 2010, the SDO has helped us “understand where the Sun’s energy comes from, how the inside of the Sun works, and how energy is stored and released in the Sun’s atmosphere.”
The work done by the SDO helps us better understand and forecast space weather, which not only affects the astronauts and satellites out in space but life on Earth and Earth itself.
The SDO is a geostationary satellite, meaning it rotates at the same speed of Earth, and this puts it directly above its ground station in New Mexico at all times, to which it constantly sends data.
How does the SDO capture images?
The SDO has three key instruments onboard, two of which are used for high-definition imagery:
- Helioseismic and Magnetic Imager (HMI) — The role of the HMI is to measure the ripples and magnetic fields on the surface of the Sun by using different wavelengths. Using this information on what’s happening on the surface, scientists try to figure out what is happening on the inside of the Sun. It’s like taking an ultrasound picture of the Sun.
- Atmospheric Imaging Assembly (AIA) — The AIA takes pictures of the outer layer of the Sun’s atmosphere, the corona, at a wide range of temperatures and at highly-frequent intervals. The secret to capturing the sun is to capture light we humans can’t see. These are ultraviolet and infrared light. The AIA has four telescopes fitted with special filters that only allow extreme ultra-violet light to get through. These telescopes capture images at 10 different wavelengths every 12 seconds and they have a spatial resolution of 725 km.
Together these instruments send back images at thirteen different wavelengths, which each reveal different aspects of the Sun.
The time-lapse released by NASA was made with photos taken at a wavelength of 17.1 nanometers, labeled as AIA 171 in the above image.
The colors of the different wavelengths, although dazzling, are completely artificial. Since our eyes cannot see these wavelengths of light, there is no offical color assigned to them. NASA arbitrarily color codes them with the vibrant colors shown above so that they’re not just black and white images.
How much data does the SDO send back to Earth?
The SDO was designed to send unprecedented amounts of data back to Earth, 50 times more data than any other NASA mission at the time of its launch, and enough to fill a single CD every 36 seconds.
It amasses this data by capturing an image of the Sun every 0.75 seconds. These images are captured at a resolution 10 times greater than that of a standard high-definition picture and sent to the ground station in New Mexico at a speed of 130 Mbps.
This has allowed NASA to gather a mammoth 425 million high-resolution images that total 20 million gigabytes, or 20 petabytes, over the last ten years.
To put that in context, that’s equivalent to 5 million HD movies, each around 4 GB in size. And to put that in further context: Netflix’s entire US catalog is close to merely 4,000 movies.
Or picture this: if 20 petabytes worth of 1 GB flash drives were lined up end to end, it would stretch 1,840 football fields!
Yet another comparison: the human brain’s memory capacity is said to be equivalent to 2.5 petabytes of data.
How does the work of the SDO matter?
Our society depends heavily on things like electricity, wireless communication, GPS navigation, and air travel — all of which can be brought down by intense solar activity. A solar storm can cause twenty-times more damage than Hurricane Katrina. The SDO allows us to predict such a storm and be prepared for it.
NASA highlights ten of the most important things we’ve learned from the SDO in the last decade in this video:
Although the SDO was designed to fly for 5 years, it has long outlived this expectation and is fit to stay functional for another decade from now. In 2030, we can look forward to another such time-lapse, and hopefully, learn a lot more about the star that sustains life on Earth. Until then, this time-lapse lets us safely stare at the Sun with our naked eye for as long as we want.