Tabla de contenidos para March 2023 en Astronomy

WHEN COSMIC RAYS run into dust and radiation, they produce particles that eventually decay into gamma rays and neutrinos. These messengers flood the cosmos from all directions. But while gamma rays can be readily detected, neutrinos — which rarely interact with matter — are much harder. Until recently, astronomers could point confidently to just one galaxy known to produce them. Now, there is strong evidence for a second: the bright spiral M77 (NGC 1068) in Cetus, around 45 million light-years away. In a paper published Nov. 3 in Science, researchers report fresh observations from the IceCube neutrino observatory at the South Pole, plus improved analysis techniques that draw on machine learning. Combined, the results indicate M77 is the origin of 79 neutrinos that IceCube detected over the past decade. The IceCube…

THE PLANETS IN THEIR ORBITS Arrows show the inner planets’ monthly motions and dots depict the outer planets’ positions at midmonth from high above their orbits. THE PLANETS IN THE SKY These illustrations show the size, phase, and orientation of each planet and the two brightest dwarf planets at 0h UT for the dates in the data table at bottom. South is at the top to match the view through a telescope. JUPITER’S MOONS Dots display positions of Galilean satellites at 9 P.M. EDT on the date shown. South is at the top to match the view through a telescope.…

THE AUG. 21, 2017, total solar eclipse that swept across the U.S. revealed a need for a great deal of astronomy education for the general public. The lower 48 states had not seen solar totality since 1979, and people everywhere were clamoring for information on where they needed to be to see totality, what causes eclipses, and how to watch one safely. And, in retrospect, the astronomy community generally delivered fantastically well on all these accounts. Dan McGlaun, a veteran of 14 total solar eclipses, participated in that effort by operating the now-defunct site www.eclipse2017.org, which (with over 200 million hits) successfully provided education and outreach for the 2017 total eclipse. For the 2023 and 2024 eclipses, he’s created www.eclipse2024.org to host information on the events. Meet the Simulator A major…

SEND YOUR IMAGES TO: Astronomy Reader Gallery, P.O. Box 1612, Waukesha, WI 53187. Please include the date and location of the image and complete photo data: telescope, camera, filters, and exposures. Submit images by email to readergallery@astronomy.com.…

Following Jupiter Although I have been gazing up at the night sky since I was quite young, my wife of 48 years never seemed as interested. However, after I shared details in Michael Bakich’s October article, “Hail to the king,” and explained Jupiter’s location with respect to the Moon’s location (based on Martin Ratcliffe’s and Alister Ling’s summary in Sky This Month), she immediately picked out Jupiter on her own! And ever since that evening, she has been looking up to locate and observe Jupiter with very special excitement. —Glenn Luzzi, Mount Bethel, PA Certain uncertainty Just got my October copy of Astronomy with Stephen O’Meara’s column on uncertainty. Wow, did it get me thinking about looking up into the sky and being uncertain about what I am seeing! Sometimes,…

» NASA has finally taken its first small step toward sending humans back to the Moon. Over the course of a 25-day flight, the uncrewed Artemis 1 mission launched aboard NASA’s brand-new Space Launch System (SLS), looped around the Moon twice thanks to the European-built Service Module, and splashed down with the Orion capsule off Mexico’s Baja California coast on Dec. 11 — the 50th anniversary of the Apollo 17 Moon landing. In the runup to the launch, NASA officials had emphasized that the mission was a test flight. “We are stressing Orion beyond what it was designed for,” said Bob Cabana, NASA’s associate administrator, at a briefing. But Artemis 1 passed with flying colors, proving that the hardware meant to fly humans to the Moon is up to the…

We all survey the vastness of space with a certain amount of wonder and awe. Exploring and understanding the cosmos requires units to express its size — including volume. But because of that vastness, we often revert to nonstandard metaphors to help convey it. To express the volume of something big, like the Sun for example, writers commonly say that a million planet Earths would fit inside it. Tiny objects demand similarly creative analogies. The universe contains mostly hydrogen atoms, whose mass is concentrated in the nucleus, usually as a single proton. That proton is 1,836 times heavier than the electron buzzing around it. But a true picture requires us to also visualize its structure, which is mostly empty space. We’d succeed by representing that proton as a raisin in…

MILLIONS OF PEOPLE throughout the U.S. experienced the much-anticipated total solar eclipse of Aug. 21, 2017, the first to cross the country since 1979. And, if you saw the 2017 eclipse, you’re no doubt already planning to head to the path of totality when the Moon’s shadow again crosses the contiguous 48 states on April 8, 2024. If you skipped the last one, keep in mind that there won’t be another cross-country eclipse for two decades — don’t miss out this time! The nitty-gritty Every eclipse has a different length of totality. This is caused by the nature of the cosmos as Earth and the Moon orbit not in perfect circles, but ellipses — so Earth is not always the same distance from the Sun and the Moon is not…

The dynamic interplay of l ig ht a nd shadow across the lunar face is a perpetual source of visual wonder — and, sometimes, puzzlement. Nearly 40 years ago, Terry Atwood of Shreveport, Louisiana, saw one such display in the crater Hypatia. The feature lies in a tiny promontory of equatorial lunar highland, just south of the Apollo 11 landing site in Mare Tranquillitatis (Sea of Tranquillity). The crater’s name honors Hypatia of Egypt (circa a.d. 370–415), the first woman known to have made a substantial contribution to the development of mathematics. Under the right geometry, a ray of sunlight can slice across Hypatia’s otherwise shadowed crater floor. Such an event is likely best seen around a solar colongitude of 350° (or about 10° shy of First Quarter) — with…

NASA’s Lucy spacecraft captured this view of Earth, the Moon, and the vast desert between them from a distance of 890,000 miles (1.4 million kilometers) Oct. 13. The spacecraft was approaching Earth to execute its first of three planned gravity assists, which will boost it to the speeds needed to reach Jupiter’s orbit. The Lucy mission is designed to explore one main-belt asteroid and several of Jupiter’s Trojan asteroids, which form two camps that lead and follow the gas giant in its orbit around the Sun.…

ON THE NIGHT OF MAY 25, 2019, astronomy educator Victoria Girgis was conducting a public stargazing session at Lowell Observatory in Flagstaff, Arizona. A telescope and camera were trained on NGC 5353/4, a magnitude 11 galaxy group in Canes Venatici, when suddenly the image was photobombed by an extremely bright train of satellites streaking through the field of view. Around the world, astronomers were seeing the same thing — and quickly realized the culprit: Just two days earlier, SpaceX had launched a Falcon 9 rocket carrying the first 60 satellites of the company’s new Starlink satellite system, designed to provide broadband internet access around the world. The astronomy community and SpaceX were both caught by surprise at just how bright these new satellites were. Prior to 2019, there were only…

AS HUMANS HAVE EVOLVED ON EARTH, many naturally occurring events — earthquakes, volcanoes, destructive weather — have struck fear into their hearts. At the top of the list, I contend, is the disappearance of the life-giving Sun from the midday sky during a total solar eclipse. Even today, the drama of such phenomena compels people to travel halfway around the globe to witness them. But which eclipses throughout history are the most noteworthy? For this list, I’ve chosen to include eclipses you might not be familiar with, including many that happened before the invention of the telescope. As you read through them, particularly the earliest accounts, try to imagine standing in darkness beneath the Moon’s shadow for a few fleeting minutes — which, in the minds of those terrified souls, must…

Q | SINCE THEY LACK DARK MATTER AND CENTRAL BLACK HOLES, HOW DID GLOBULAR CLUSTERS FORM? Sasi K. Chandran Wake Forest, North Carolina A | Globular clusters are the fossils of the astronomical world. We know they are very old, having formed shortly after the Big Bang. Furthermore, they must be pretty robust, since many have survived until the present day. But the exact details of how these clusters formed is still the subject of much research. Observations of nearby globulars indicate that they do not contain dark matter, but that does not preclude them having formed originally within mini dark-matter halos. However, we see young (i.e., a few billion years old) star clusters within the Magellanic Clouds with many of the characteristics of globular clusters. In other words, if we could…