Comet H2 Lemmon Brightens in Early November Ahead of Expectations

Comet H2 Lemmon
Comet H2 Lemmon passes near the galaxy NGC 4258 on October 12th. Credit: Dan Bartlett

Discovered early this year, Comet C/2023 H2 Lemmon may approach naked eye brightness this month.

A comet discovered earlier this year is performing above expectations, and is currently well-placed in the dusk sky. We’re talking about Comet C/2023 H2 Lemmon, moving up the charts now at magnitude +8 and brightening.

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A Dwarf Galaxy That's Almost All Dark Matter

A simulation of dark matter clusters around the Milky Way. Credit: J. Tumlinson (STScI)

Dark matter is a powerful cosmological model, but it isn’t without its problems. In addition to our inability to detect dark matter particles, one issue deals with the number of dwarf galaxies surrounding the Milky Way. According to the most popular models of dark matter, galaxies should be surrounded by clumps of dark matter within their dark matter halo. Since regular matter tends to gather around dark matter, that means the Milky Way should be surrounded by dwarf galaxies. While there are several known dwarf galaxies near the Milky Way, there are fewer than predicted by dark matter simulations. But perhaps there are many more dwarf galaxies we just haven’t noticed because they are made mostly of dark matter.

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Devastating Clouds of Dust Helped End the Reign of the Dinosaurs

Paleoart reconstruction depicting North Dakota in the first months following the Chicxulub impact event 66 million years ago, showing a dark, dusty, and cold world in which the last non-avian dinosaurs, illustrated with a Dakotaraptor steini, were on the edge of extinction. Artwork by Mark A. Garlick.

When a giant meteor crashed into Earth 66 million years ago, the impact pulverized cubic kilometers of rock and blasted the dust and debris into the Earth’s atmosphere. It was previously believed that sulfur from the impact and soot from the global fires that followed drove a global “impact winter” that killed off 75% of species on Earth, including the dinosaurs.

A new geology paper says that the die-off was additionally fueled by ultrafine dust created by the impact which filled the atmosphere and blocked sunlight for as long as 15 years. Plants were unable to photosynthesize and global temperatures were lowered by 15 degrees C (59 F).

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A Collapsed Martian Lava Chamber, Seen From Space

This HiRise image of Hephaestus Fossae shows a volcanic area that's collapsed into a pit. We should explore it. Image Credit: NASA/JPL-Caltech/UArizona

Lava tubes and chambers attract a lot of attention as potential sites for bases on the Moon and Mars. They provide protection from radiation, from temperature swings, and even from meteorites. They beg to be explored.

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Next Generation Gravitational Wave Observatories Could Detect 100-600 Solar Mass Black Hole Mergers

Simulation of merging supermassive black holes. Credit: NASA's Goddard Space Flight Center/Scott Noble
Simulation of merging supermassive black holes. New research shows how dark matter overcomes the Final Parsec Problem. Credit: NASA's Goddard Space Flight Center/Scott Noble

Humans are born wonderers. We’re always wondering about the next valley over, the next horizon, what we’ll understand next about this vast Universe that we’re all wrapped up in.

In 2015, we finally detected our first long-awaited and long-theorized gravitational wave from the distant merger of two stellar mass black holes. But now we want to know more, and only better detectors can feed our appetite.

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White Dwarfs Could Support Life. So Where are All Their Planets?

Artist's view of old white dwarfs surrounded by planetary debris. Credit: University of Warwick/Dr Mark Garlick

Astronomers have found plenty of white dwarf stars surrounded by debris disks. Those disks are the remains of planets destroyed by the star as it evolved. But they’ve found one intact Jupiter-mass planet orbiting a white dwarf.

Are there more white dwarf planets? Can terrestrial, Earth-like planets exist around white dwarfs?

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Can There Be Double Gravitational Lenses?

The narrow galaxy elegantly curving around its spherical companion in this image is a fantastic example of a truly strange and very rare phenomenon. This image, taken with the NASA/ESA Hubble Space Telescope, depicts GAL-CLUS-022058s, located in the southern hemisphere constellation of Fornax (The Furnace). GAL-CLUS-022058s is the largest and one of the most complete Einstein rings ever discovered in our Universe. The object has been nicknamed by the Principal Investigator and his team who are studying this Einstein ring as the "Molten Ring", which alludes to its appearance and host constellation. First theorised to exist by Einstein in his general theory of relativity, this object’s unusual shape can be explained by a process called gravitational lensing, which causes light shining from far away to be bent and pulled by the gravity of an object between its source and the observer. In this case, the light from the background galaxy has been distorted into the curve we see by the gravity of the galaxy cluster sitting in front of it. The near exact alignment of the background galaxy with the central elliptical galaxy of the cluster, seen in the middle of this image, has warped and magnified the image of the background galaxy around itself into an almost perfect ring. The gravity from other galaxies in the cluster is soon to cause additional distortions. Objects like these are the ideal laboratory in which to research galaxies too faint and distant to otherwise see.
Gravitational Lens GAL-CLUS-022058s taken with NASA/ESA Hubble Space Telescope

If you, like me, have used telescopes to gaze out at the wonders of the Universe, then you too may have been a little captivated by the topic of gravitational lensing.  Think about it: how cool is it that the very universe we are trying to explore is actually providing us with telescopes to probe the darkest corners of space and time? 

The alignment of large clusters of galaxies is the usual culprit whose gravity bends distant light to give us nature’s own telescopes, but now part-time theoretical physicist Viktor T Toth poses the question, “Can there be multiple gravitational lenses lined up and can they provide a ‘communication bridge’ to allow civilisations to communicate?”

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Did Betelgeuse Consume a Smaller Star?

The red supergiant Betelgeuse. Its activity can be confounding, and new research suggests that the star could've consumed a smaller companion star. Image credit: Hubble Space Telescope. Image Credit: ALMA (ESO/NAOJ/NRAO)/E. O’Gorman/P. Kervella

What’s going on with Betelgeuse? In recent years it’s generated a lot of headlines as its luminosity has shifted dramatically several times. The red supergiant brightened by almost 50% earlier this year, triggering speculation that it may go supernova.

But new research suggests there’s something completely different happening with Betelgeuse that has nothing to do with its recent fluctuations. It may have consumed a smaller companion star.

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Three Planets Around this Sunlike Star are Doomed. Doomed!

A distant Sun-like star will leave the main sequence behind, ending its life of fusion. Then it'll expand into a red giant, totally destroying its four planets. Image Credit: fsgregs Creative Commons Attribution-Share Alike 3.0 Unported

According to new research we can start writing the eulogy for four exoplanets around a Sun-like star about 57 light years away. But there’s no hurry; we have about one billion years before the star becomes a red giant and starts to destroy them.

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New Telescopes to Study the Aftermath of the Big Bang

A photograph of a CMB-S4 detector wafer being prepared for testing in a cryostat at Lawrence Berkeley National Laboratory. Credit: Thor Swift/Lawrence Berkeley National Laboratory

Astronomers are currently pushing the frontiers of astronomy. At this very moment, observatories like the James Webb Space Telescope (JWST) are visualizing the earliest stars and galaxies in the Universe, which formed during a period known as the “Cosmic Dark Ages.” This period was previously inaccessible to telescopes because the Universe was permeated by clouds of neutral hydrogen. As a result, the only light is visible today as relic radiation from the Big Bang – the Cosmic Microwave Background (CMB) – or as the 21 cm spectral line created by the reionization of hydrogen (aka. the Hydrogen Line).

Now that the veil of the Dark Ages is being slowly pulled away, scientists are contemplating the next frontier in astronomy and cosmology by observing “primordial gravitational waves” created by the Big Bang. In recent news, it was announced that the National Science Foundation (NSF) had awarded $3.7 million to the University of Chicago, the first part of a grant that could reach up to $21.4 million. The purpose of this grant is to fund the development of next-generation telescopes that will map the CMB and the gravitational waves created in the immediate aftermath of the Big Bang.

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