Comets have long been seen as omens and portents, and it’s easy to understand why. They first appear as faint smudges of light in the sky, sometimes fading soon after and sometimes becoming brighter than the planets, with a long, glowing tail. They have been observed throughout human history, but it wasn’t until the eighteenth century that astronomers began to predict the return of some comets. Even today, we can’t predict the return of most comets until after they swing through the inner solar system. If such a comet happens to be heading toward Earth, we wouldn’t know about it until too late. But that could change thanks to our observations of meteor showers.
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Comet C/2023 A3 Tsuchinshan-ATLAS survived perihelion to become a fine dusk object for northern hemisphere observers.
One of my favorite paintings is Starry Night by Vincent van Gogh — for obvious astronomical reasons. But another favorite of van Gogh’s works is Lane of Poplars at Sunset. This painting depicts the setting Sun perfectly aligned with a long lane of trees, casting long shadows.
In the summer of ’69, Apollo 11 delivered humans to the surface of the Moon for the first time. Neil Armstrong and Buzz Aldrin spent just over two hours exploring the area near their landing site on foot. Only during Apollo 15, 16, and 17 did astronauts have a vehicle to move around in.
In June 2018, Japan’s Hayabusa 2 mission reached asteroid 162173 Ryugu. It studied the asteroid for about 15 months, deploying small rovers and a lander, before gathering a sample and returning it to Earth in December 2020.
Neutron stars are as dense as the nucleus of an atom. They contain a star’s worth of matter in a sphere only a dozen kilometers wide. And they are light-years away. So how can we possibly understand their interior structure? One way would be to simply spin it. Just spin it faster and faster until it reaches a maximum limit. That limit can tell us about how neutron stars hold together and even how they might form. Obviously, we can’t actually spin up a neutron star, but it can happen naturally, which is one of the reasons astronomers are interested in these maximally spinning stars. And recently a team has discovered a new one.
Carbon is the building block for all life on Earth and accounts for approximately 45–50% of all dry biomass. When bonded with elements like hydrogen, it produces the organic molecules known as hydrocarbons. When bonded with hydrogen, oxygen, nitrogen, and phosphorus, it produces pyrimidines and purines, the very basis for DNA. The carbon cycle, where carbon atoms continually travel from the atmosphere to the Earth and back again, is also integral to maintaining life on Earth over time.
The Solar System’s hundreds of moons are like puzzle pieces. Together, they make a picture of all the forces that can create and modify them and the forces that shape our Solar System. One of them is Miranda, one of 28 known moons that orbit the ice giant Uranus. Miranda is its smallest major moon, at 471 km in diameter.
Saturn’s moon, Titan, is an anomaly among moons. No other moons have surface liquids, and aside from Earth, it’s the only other Solar System object with liquids on its surface. However, since Titan is so cold, the liquids are hydrocarbons, not water. Titan’s water is all frozen into a surface layer of ice.
In May 2023, the ESA’s Exomars Trace Gas Orbiter (TGO), currently in orbit around Mars, sent a signal to Earth to simulate a possible extraterrestrial transmission. As part of the multidisciplinary art project “A Sign in Space,” the purpose was to engage citizen scientists in helping to decode it. The campaign was inspired by Cosmicomics by Italian writer/journalist Italo Calvino, a series of short stories exploring various scientific principles. The project is partnered with the SETI Institute, the Green Bank Observatory, the European Space Agency (ESA), and the Istituto Nazionale di Astrofisica (INAF).
Though there are no firm plans for a crewed mission to Mars, we all know one’s coming. Astronauts routinely spend months at a time on the ISS, and we’ve learned a lot about the hazards astronauts face on long missions. However, Mars missions can take years, which presents a whole host of problems, including astronaut nutrition.
In 1181, Japanese and Chinese astronomers saw a bright light appear in the constellation Cassiopeia. It shone for six months, and those ancient observers couldn’t have known it was an exploding star. To them, it looked like some type of temporary star that shone for 185 days.
This idea really is quite a fascinating one. Currently a trip to Mars would require large amounts of air, water and other resources to sustain human life but would also expose travellers to harmful levels of radiation. A wonderful solution has been proposed in a new paper recently published by researchers from Ukraine. They propose that asteroids which already travel relatively close by Earth, Mars and even Venus already could be used to hop between the planets. They are already making the journey anyway and so perhaps the cosmos already provides the solution to interplanetary travel.
To northern sky watchers, Vega is a familiar sight in the summer sky. It’s one of the brightest stars in the sky and in 2013, astronomers detected a large ring of rocky debris surrounding the planet. The prospect of planets suddenly became a real possibility so astronomers turned the James Webb Space Telescope (JWST) on the star. The hunt achieved 10 times the sensitivity of previous ground based searches but alas no planets were discovered.
The TRAPPIST-1 system is a science-fiction writer’s dream. Seven Earth-sized worlds orbit a red dwarf star just 40 light-years away. Three of those worlds are within the habitable zone of the star. The system spans a distance less than 25 times that of the distance from the Earth to the Moon. Oh, what epic tales a TRAPPIST civilization would have! That is, if life in such a system is even possible…
Exoplanets are a fascinating aspect of the study of the Universe. TRAPPIST-1 is perhaps one of the most intriguing exoplanet systems discovered to date with no less than 7 Earth-sized worlds. They orbit a red dwarf star which can unfortunately be a little feisty, hurling catastrophic flares out into space. These flares could easily strip atmospheres away from the alien worlds rendering them uninhabitable. A new piece of research suggests this may not be true and that the rocky planets may be able to maintain a stable atmosphere after all.
Infrared astronomy has revealed so much about the Universe, ranging from protoplanetary disks and nebulae to brown dwarfs, aurorae, and volcanoes on together celestial bodies. Looking to the future, astronomers hope to conduct infrared studies of supernova remnants (SNRs), which will provide vital information about the physics of these explosions. While studies in the near-to-mid infrared (NIR-MIR) spectrum are expected to provide data on the atomic makeup of SNRs, mid-to-far IR (MIR-FIR) studies should provide a detailed look at heated dust grains they eject into the interstellar medium (ISM).
Moons are the norm in our Solar System. The International Astronomical Union recognizes 288 planetary moons, and more keep being discovered. Saturn has a whopping 146 moons. Every planet except Mercury and Venus has moons, and their lack of moons is attributed to their small size and proximity to the Sun.
Remember that amazing “first image” of Sagittarius A* (Sgr A) black hole at the heart of the Milky Way? Well, it may not be completely accurate, according to researchers at the National Astronomical Observatory of Japan (NAOJ). Instead, the accretion disk around Sgr A* may be more elongated, rather than the circular shape we first saw in 2022.
The odds are good that we are not alone in the Universe. We have found thousands of exoplanets so far, and there are likely billions of potentially habitable planets in our galaxy alone. But finding evidence of extraterrestrial life is challenging, and even the most powerful telescopes we currently have may not produce definitive proof. But there are telescopes in the pipeline that may uncover life. It will be decades before they are built and launched, but when they are, which systems should they target first? That’s the question answered in a recent paper.