Of all of the objects within the solar system, perhaps probably the most spectacular are the good comets that occasionally grace our skies. If you happen to’ve been on social media up to now few days, you’ve got probably seen articles proclaiming we’ve such a comet in our skies without delay: C/2023 P1 (Nishimura).
As I write this, Comet Nishimura is swinging past on its first visit in greater than 400 years. Japanese astronomer Hideo Nishimura discovered the comet on Aug. 12. Soon after, pre-discovery images of the comet dating back to January were found, allowing astronomers to find out its path.
They quickly realized Nishimura would swing closer to the sun than the orbit of Mercury this month. Given the comet’s brightness on the time of discovery, it could turn into brilliant enough to see with the naked eye. So, will or not it’s a spectacular sight in our skies? Probably not.
Unfortunately, Nishimura’s path will keep it near the sun within the sky as observed from Earth. While it’s definitely brilliant enough to be visible to the naked eye in dark skies, at best it’s going to hug the horizon just after sunset – almost lost within the sun’s glow.
Still, astronomers across the globe are excited. Even a hard-to-spot naked-eye comet is value observing. And as science author and astronomer David H. Levy once said: “Comets are like cats: they’ve tails, and so they do precisely what they need.”
There is a probability Nishimura might brighten unexpectedly. If it does, we would see something special within the couple of weeks. If not, there’s at all times next 12 months – but more on that later.
Recipe for a brilliant comet
Comets are like cats: they’ve tails, and so they do precisely what they need.”
— David Levy
After they are removed from the sun, within the icy depths of space, comets are essentially dirty snowballs: lumps of ice, dust and rock left over from the solar system’s formation.
As a comet approaches the sun, its surface begins to heat up. The ices near the surface get hot and “sublime,” turning to gas and erupting outward from the comet’s surface. This gas carries dust and debris, shrouding the nucleus in a diaphanous cloud of gas and mud called a “coma.”
The solar wind then blows the gas and mud away from the sun, which provides the comet its tail (or tails). The tails point away from the sun.
The comet we see is sunlight being reflected from the gas and mud within the coma and tails – the nucleus itself is hidden from sight. A comet’s brightness, subsequently, is often determined by three things:
- the dimensions of the nucleus: a much bigger nucleus typically means a bigger energetic area (though some comets are more energetic than others) and more gas and mud production;
- distance to the sun: the closer the comet is to the sun, the more energetic (and brighter) it’s going to turn into;
- distance to Earth: the closer the comet is to us, the brighter it’s going to appear.
What about Nishimura?
That brings us to Comet Nishimura. It seems likely Nishimura is not that giant – otherwise we might have spotted it sooner – neither is it particularly near Earth. It’s, nonetheless, passing relatively near the sun and is anticipated to be very energetic around perihelion (its closest point to the sun).
Were it possible to view in a dark night sky, the comet can be quite impressive. Sadly, even at its best Nishimura will probably be near the sun within the sky.
On top of that, it just so happens the comet and Earth are situated at in regards to the worst orientation for viewing: Nishimura will stay near the sun because it recedes from us, remaining buried within the star’s glare.
A brief window to see Nishimura from Australia
Nishimura will soon peek above the western horizon after sunset, but only just. One of the best probability to see it from Australia is available in the week of Sept. 20 to 27, when the comet’s head will set around one hour after the sun. It can be farthest from the sun within the evening sky on Sept. 23.
As twilight ends, Nishimura will probably be very near the western horizon, about to set. Meaning it’s going to probably be lost within the sun’s glare.
But remember, comets are like cats. Some comets disintegrate when at their closest to the sun, wherein case they often brighten significantly. If that were to occur to Nishimura, it could turn into much easier to identify.
Unfortunately, the comets almost definitely to fragment are those visiting the inner solar system for the primary time, moving on very long-period orbits of tens or lots of of 1000’s of years. Nishimura is a seasoned visitor, with an orbital period of around 430 years. It has likely swung past the sun repeatedly and survived, which lowers the percentages of it breaking apart.
Nonetheless, while the top of the comet could be lost within the twilight, the tail might still be visible because the sky darkens. Before the comet was lost within the glare to northern hemisphere viewers, observers put its tail at around six degrees in length – and it’s going to likely grow because the comet swings closer to the Sun.
If you happen to’re lucky, you may spot the tail standing proud above the horizon because the sky darkens.
The following great comet
If Nishimura doesn’t turn into the show you hoped for, there is a probability one other comet could placed on a very spectacular show next 12 months. Comet C/2023 A3 (Tsuchinshan-ATLAS) was discovered at first of this 12 months. It’s currently almost as removed from the Sun as Jupiter.
Over the subsequent 12 months it’s going to proceed to fall sunward, coming closest to the sun in late September 2024. Tsuchinshan-ATLAS is looking promising. If it behaves as expected it may very well be a spectacular sight – but just remember: comets are like cats!
Take a look at our guides to the best binoculars and the best telescopes to assist find the correct telescope for you. And in case you’re seeking to take photos of Comet Nishimura or the night sky typically, try our guide on learn how to photograph comets, in addition to our best cameras for astrophotography and best lenses for astrophotography.
Editor’s Note: If you happen to snap a picture of Comet Nishimura and would love to share it with Space.com’s readers, send your photo(s), comments, and your name and placement to spacephotos@space.com.