Why You Can’t See The New Supernova With Just Your Naked Eyes

A supernova called SN 2023ixf has appeared in the outskirts of a beautiful spiral galaxy in the night sky.

The exploding supergiant star—the result of its core collapsing under its own gravity—can be seen in the night sky, but it takes something more than clear skies and wide eyes to see it.

“You won’t be able to see this supernova with the naked eye,” wrote Andy Howell, an astronomer at Las Cumbres Observatory, on Twitter. “You need a supernova in our galaxy, or a satellite galaxy right next door for that.”

Observing the supernova

SN 2023ixf is in the Pinwheel Galaxy (M101), a particularly gorgeous galaxy very close to the handle of the Big Dipper. Even if there was no supernova it’s worth pointing a telescope it.

That’s because M101 is a grand spiral galaxy, with arms full of stars. From the solar system we get a face-on view of it from the top/bottom.

SN 2023ixf itself is merely a point of light, but it’s currently brightening and it outshines anything else in the galaxy. “This new supernova will increase in brightness over the coming days,” wrote Howell. “You should be able to see it with backyard telescopes, for a few months.”

A rare glimpse

Supernovas are relatively rare to see and almost always seen in other galaxies.

The best view modern astronomers have ever had of a supernova was in 1987 when a massive star exploded in the Large Magellanic Cloud (LMC), a dwarf galaxy that orbits our Milky Way galaxy. The LMC can be easily seen from the southern hemisphere, so SN 1987A presented astronomers with a rare opportunity to study the phases before, during and after the death of a star.

There’s been nothing that close since. In fact, a supernova hasn’t been seen within the Milky Way since 1604 when German astronomer Johannes Kepler observed observed one shining in daylight for three weeks.

Supernova remnants

Supernovae may be rare close to the solar system, but they have left their marks all over the night sky.

The most famous supernova seen from Earth occurred in 1054. Its remnants can still be seen as the Crab Nebula (M1) in the constellation of Taurus.

A cloud of gas and dust expanding into space with a spinning pulsar at its core, we know it was seen by humans because records of a “guest star” appearing have been found in texts in East Asia.

Ancient observations

The 1054 supernova—which shone for 23 days and was 10 times brighter than Venus—may also be depicted in a pictograph in the southwest US. An image in Chaco Canyon, New Mexico created on a rocky overhang by Ancestral Puebloan culture depicts a star-shape next to a crescent moon beneath a life-size hand print. That tallies with the exact predicted date of the supernova—July 4, 1054—when, the following night, the moon was just three degrees from where the supernova would have been.

Early warning system

Whether a star in the Milky Way goes supernova anytime soon is anyone’s guess. A prime candidate is Betelgeuse, the closest red supergiant star to the solar system at around 550 light-years that is expected to go supernova within the next 100,000 years. It displayed some odd behavior in 2019-2020, but did not explode.

When a close star does explode we may get some warning. Modern neutrino detectors should be able to detect a star spewing neutrinos in the moments before it collapses in a supernova explosion. Supernovas are thought to be the most frequent source of cosmic neutrinos in the universe.

With the “kill zone” for a supernova about 40 light-years, Earth will be safe—and we’ll all get a great naked-eye view of a bright “guest star” in daylight. Until then, feast your eyes on SN 2023ixf through any small telescope.

Wishing you clear skies and wide eyes.

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