Amateur astronomer discovers bright green comet SWAN25F — and you can see it too
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An amateur astronomer has discovered a bright green comet dive-bombing toward the inner solar system. The emerald-colored object will slingshot around the sun in less than a month, when it could become visible to the naked eye — but anyone with decent backyard gear may be able to see it now.
The new comet, dubbed SWAN25F, was discovered April 1 by Australian amateur astronomer Michael Mattiazzo, who noticed the comet in photos captured by the SWAN camera on the European Space Agency's Solar and Heliospheric Observatory (SOHO) spacecraft, according to Spaceweather.com.
Multiple astronomers have since confirmed SWAN25F's existence, but the comet has not yet been officially recognized by NASA's Minor Planets Center. As a result, there are still large gaps in what we know about this object's size, origin, distance, speed and orbit. But researchers have started to piece together its trajectory through the solar system and believe it will reach perihelion — its closest point to the sun — on May 1 and reach a minimum distance of around 31 million miles (50 million kilometers) from our home star.
News of the potential new comet spread quickly, enabling multiple astrophotographers to capture striking pictures of the comet just days after it was discovered, Live Science's sister site Space.com reported. The green comet has also been snapped by the Virtual Telescope Project in Manciano, Italy.
One of the best photos of SWAN25F so far was captured by astrophotographers Michael Jäger and Gerald Rhemann from Weißenkirchen, Austria (see above).
Related: 'Totally amazing' astronaut photo captures comet C/2024 G3 ATLAS shooting past Earth from the ISS
Based on that photo, SWAN25F likely has a tail spanning up to 2 degrees across the night sky, Jäger told Live Science. That is quite significant for a comet this far from the sun, although the tail is currently quite faint, he added.
The comet's emerald glow is likely the result of dicarbon — a form of carbon where a pair of atoms are double-bonded to one another, which has been known to give off a green color in other comets.
Initial observations of SWAN25F revealed that the comet had an apparent magnitude of around +10, but it has quickly brightened to less than +8. (Apparent magnitude is measured relative to the brightest objects in the night sky, which have a value of zero. The brighter the comet gets, the lower its magnitude will get.)
"The comet appears to be brightening quite quickly," Nick James, the director of the comets section at the British Astronomical Association, told Spaceweather.com earlier in the week. "It is too early to predict what the peak brightness will be. We need a few more days of observations to confirm the current trend, but it should become at least a binocular object."
But James' prediction has already come true, as the comet can now be seen with a decent pair of stargazing binoculars or a decent telescope, EarthSky.com reported. The website has also mapped where the comet can be seen over the next few days.
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The comet will continually brighten as it approaches perihelion, and Jäger predicts that it could peak at around +5, which would make it visible to the naked eye. However, the comet's position puts it close to the horizon in the night sky, which could make it hard to spot.
As researchers continue to study SWAN25F, it will become clearer when and where the comet will be most visible.
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This can create several problems, including an increase in space junk, rising light pollution in the night sky and a build-up of metal pollution in the upper atmosphere from satellite reentries. A lesser-known issue is that private satellites are prone to accidentally leaking radiation into space, which can interfere with radio telescopes trying to study distant objects such as ancient galaxies, nearby exoplanets and supermassive black holes. Several radio astronomers recently told Live Science that, if the number of satellites around our planet reaches maximum capacity, we could reach an "inflection point" beyond which radio astronomy would be extremely limited, and even impossible in some wavelengths. If this were to happen, "it would mean that we are artificially closing 'windows' to observe our universe," Federico Di Vruno, an astronomer at the Square Kilometer Array Observatory and co-director of the International Astronomical Union's Center for the Protection of the Dark and Quiet Sky, told Live Science. Having a shielded telescope on the moon could allow radio astronomy to persist even if this worst-case scenario comes to pass. However, this one telescope would only allow us to do a fraction of the science currently being achieved by radio observatories across the globe, meaning our ability to study the cosmos would still be drastically limited. Other researchers are also exploring the possibility of using a constellation of moon-orbiting satellites, as an accompaniment or alternative to the LCRT, Gupta said. However, these will likely have a much reduced window for observations than the larger telescope. In addition to preserving radio astronomy, LCRT could also allow us to scan wavelengths that Earth-based telescopes cannot. Radio signals with wavelengths greater than 33 feet (10 m), known as ultra-long wavelengths, do not easily pass through Earth's atmosphere, making them almost impossible to study from the ground. But these wavelengths are also vital in studying the very beginning of the universe, known as the cosmic dark ages, because signals from this epoch have been extremely red-shifted, or stretched out, before they reach us. "During this phase, the universe primarily consisted of neutral hydrogen, photons and dark matter, thus it serves as an excellent laboratory for testing our understanding of cosmology," Gupta said. "Observations of the dark ages have the potential to revolutionize physics and cosmology by improving our understanding of fundamental particle physics, dark matter, dark energy and cosmic inflation." The LCRT would also be shielded from solar radiation, which can also interfere with some other radio signals, allowing those wavelengths to be more easily studied on the moon. If LCRT is approved it will be a major coup for science. But it will not actually be the first lunar radio telescope. In February 2024, Intuitive Machine's Odysseus lander — the first private spacecraft to land on the moon and the first American lunar lander for more than 50 years — carried NASA's first Radiowave Observations on the Lunar Surface of the photo-Electron Sheath (ROLSES-1) instrument to the moon's near side. Despite the fact that the lander face-planted and ended up tilted on its side, the 30-pound (14 kilogram) telescope was still able to briefly collect the first lunar radio data. However, because ROLSES-1 was facing Earth, almost all the signals it collected came from our own planet, offering little astronomical value, according to a study uploaded March 12 to the pre-print journal arXiv. "This is a good demonstration of why we need to be on the far side for reliable measurements of the dark ages signal in a radio-quiet environment," Gupta said RELATED STORIES —Radio signal from 8 billion light-years away could reveal the secrets of the universe's 'dark age' —Astronomers discover new 'odd radio circle' near the center of our galaxy —Strange radio signals detected from Earth-like planet could be a magnetic field necessary for life Later this year, Firefly Aerospace's Blue Ghost II lander will also attempt to land on the moon's far side. Among its scheduled payloads is the Lunar Surface Electromagnetics Experiment-Night (LuSEE Night) — a mini radio telescope from the U.S. Department of Energy that will scan the sky for ultra-long-wavelength signals, Live Science's sister site previously reported. "The observations from these telescopes would be valuable for understanding the lunar environment, and the challenges and potential mitigation strategies to detect ultra-long wavelength signals," Gupta said.
