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Showing posts from April, 2025
Why are there so many moonquakes? Analyses of seismometers left on the moon during the Apollo moon landings reveal a surprising number of moonquake s occurring within 100 kilometers of the surface. In fact, 62 moonquakes were detected in data recorded between 1972 and 1977. Many of these moonquakes are not only strong enough to move furniture in a lunar apartment , but the stiff rock of the moon continues to vibrate for many minutes, significantly longer than the softer rock earthquakes on Earth . The cause of the moonquakes remains unknown, but a leading hypothesis include tidal gravity from -- and relative heating by -- our Earth. Regardless of the source, future moon dwellings need to be built to withstand the frequent shakings. Pictured here , Apollo 11 astronaut Buzz Aldrin stands beside a recently deployed lunar seismometer , looking back toward the lunar landing module . from NASA https://ift.tt/AekENlT

A Gargoyles Eclipse

In dramatic silhouette against a cloudy daytime sky over Paris, France, gargoyles cast their monstrous gaze outward from the west facade of Notre Dame Cathedral. Taken on March 29 , this telephoto snapshot also captures the dramatic silhouette of a New Moon against the bright solar disk in a partial solar eclipse. Happening high in Parisian skies, the partial eclipse was close to its maximum phase of about 23 percent. Occurring near the end of the first eclipse season of 2025, this partial solar eclipse followed the total eclipse of the Full Moon on March 13/14. The upcoming second eclipse season of 2025 will see a total lunar eclipse on September 7/8 and partial solar eclipse on September 21. The partial solar eclipse will be seen only from locations in planet Earth's southern hemisphere. from NASA https://ift.tt/nKFbz7e

Hickson 44 in Leo

Scanning the skies for galaxies, Canadian astronomer Paul Hickson and colleagues identified some 100 compact groups of galaxies , now appropriately called Hickson Compact Groups . The four prominent galaxies seen in this intriguing telescopic skyscape are one such group, Hickson 44. The galaxy group is about 100 million light-years distant, far beyond the spiky foreground Milky Way stars, toward the constellation Leo. The two spiral galaxies in the center of the image are edge-on NGC 3190 with its distinctive, warped dust lanes, and S-shaped NGC 3187. Along with the bright elliptical, NGC 3193 (above and left) they are also known as Arp 316. The spiral toward the lower right corner is NGC 3185, the 4th member of the Hickson group. Like other galaxies in Hickson groups , these show signs of distortion and enhanced star formation , evidence of a gravitational tug of war that will eventually result in galaxy mergers on a cosmic timescale. The merger process is now understood to be a nor...

The Da Vinci Glow

A 26 hour old Moon poses behind the craggy outline of the Italian Dolomites in this twilight mountain and skyscape. The one second long exposure was captured near moonset on March 30. And while only a a sliver of its sunlit surface is visible, most of the Moon's disk can be seen by earthshine as light reflected from a bright planet Earth illuminates the lunar nearside. Also known as the Moon's ashen glow, a description of earthshine in terms of sunlight reflected by Earth's oceans illuminating the Moon's dark surface was written over 500 years ago by Leonardo da Vinci . Of course earthshine is just the most familiar example of planetshine , the faint illumination of the dark portion of a moon by light reflected from its planet . from NASA https://ift.tt/cozDuVZ
Why does Jupiter have rings? Jupiter's main ring was discovered in 1979 by NASA's passing Voyager 1 spacecraft, but its origin was then a mystery. Data from NASA's Galileo spacecraft that orbited Jupiter from 1995 to 2003, however, confirmed the hypothesis that this ring was created by meteoroid impacts on small nearby moons. As a small meteoroid strikes tiny Metis , for example, it will bore into the moon, vaporize, and explode dirt and dust off into a Jovian orbit. The featured image of Jupiter in infrared light by the James Webb Space Telescope shows not only Jupiter and its clouds , but this ring as well. Jupiter's Great Red Spot (GRS) -- in comparatively light color on the right, Jupiter's large moon Europa -- in the center of diffraction spikes on the left, and Europa's shadow -- next to the GRS -- are also visible. Several features in the image are not yet well understood , including the seemingly separated cloud layer on Jupiter's righ...