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Exploding Stars, Active Suns, and Untethered Dreams in Orbit

Explore NASA images of Cassiopeia A, yearly sunspots at solar maximum, and Bruce McCandless’s untethered spacewalk, highlighting stellar death, solar cycles, and human spaceflight milestones.

This image of the spiral galaxy IC 5332, taken by the NASA/ESA/CSA James Webb Space Telescope with its MIRI instrument, has been scaled and cropped to match the NASA/ESA Hubble Space Telescope’s view of the same galaxy.

By NASA

February 27, 2026
6:29 am
Los Angeles, CA

Explanation:Massive stars in our Milky Way Galaxy live spectacular lives. Collapsing from vast cosmic clouds, their nuclear furnaces ignite and create heavy elements in their cores. After only a few million years for the most massive stars, the enriched material is blasted back into interstellar space where star formation can begin anew. The expanding debris cloud known as Cassiopeia A is an example of this final phase of the stellar life cycle. Light from the supernova explosion that created this remnant would have been first seen in Earth’s sky about 350 years ago, although it took that light 11,000 years to reach us. This sharp NIRCam image from the James Webb Space Telescope shows the still-hot filaments and knots in the supernova remnant. The whitish, smoke-like outer shell of

Image Credit: NASA, ESA, CSA, STScI; D. Milisavljevic (Purdue University), T. Temim (Princeton University), I. De Looze (University of Gent)

Explanation:
Massive stars in our Milky Way Galaxy live spectacular lives. Collapsing from vast cosmic clouds, their nuclear furnaces ignite and create heavy elements in their cores. After only a few million years for the most massive stars, the enriched material is blasted back into interstellar space where star formation can begin anew. The expanding debris cloud known as Cassiopeia A is an example of this final phase of the stellar life cycle. Light from the supernova explosion that created this remnant would have been first seen in Earth’s sky about 350 years ago, although it took that light 11,000 years to reach us. This sharp NIRCam image from the James Webb Space Telescope shows the still-hot filaments and knots in the supernova remnant. The whitish, smoke-like outer shell of the expanding blast wave is about 20 light-years across. A series of light echoes from the massive star’s cataclysmic explosion are also identified in Webb’s detailed images of the surrounding interstellar medium.

Explanation:
How many sunspots can you see? The central image shows the many sunspots that occurred in 2025, month by month around the circle, and all together in the grand central image. Each sunspot is magnetically cooled and so appears dark and can last from days to months. Although the featured images originated from NASA’s Solar Dynamics Observatory, sunspots can be easily seen with a small telescope or binoculars equipped with a solar filter. Very large sunspot groups can even be seen with eclipse glasses. Sunspots are still counted by eye, but the total number is not considered exact because they frequently change and break up. Last year, 2025, coincided with a solar maximum, the period of most intense magnetic activity during its 11-year solar cycle. Our Sun remains unpredictable in many ways, including when it ejects solar flares that impact Earth, and how active the next solar cycle will be.

Explanation:
What would it be like to fly free in space? About 100 meters from the cargo bay of a space shuttle, Bruce McCandless II was living the dream — floating farther out than anyone had ever been before. Guided by a Manned Maneuvering Unit (MMU), astronaut McCandless, pictured, was floating free in space. During Space Shuttle mission STS-41B in 1984, McCandless and fellow NASA astronaut Robert Stewart were the first to experience such an untethered spacewalk. The MMU worked by shooting jets of nitrogen and was used to help deploy and retrieve satellites. With a mass over 140 kilograms, an MMU is heavy on Earth, but, like everything, is weightless when drifting in orbit. The MMU was later replaced with the SAFER backpack propulsion unit.