太阳极小期与太阳极大期

太阳极小期与太阳极大期

ByNASA中文

2023年12月11日 Solar Minimum versus Solar Maximum Video Credit: NASA, SDO, SVS Explanation: The surface of our Sun is constantly changing. Some years it is quiet, showing relatively few sunspots and active regions. Other years it is churning, showing many sunspots and throwing frequent Coronal Mass Ejections (CMEs) and flares. Reacting to magnetism, our Sun’s surface goes through periods of relative calm, called Solar Minimum and relative unrest, called Solar Maximum, every 11 years. The featured video shows on the left a month in late 2019 when the Sun was near Solar Minimum, while on the right a month in 2014 when near Solar Maximum. The video was taken by NASA’s Solar Dynamic Observatory in far ultraviolet light. Our Sun is progressing again toward Solar Maximum…

哈勃太空望远镜拍摄到了云中的一个星团

哈勃太空望远镜拍摄到了云中的一个星团

ByNASA中文

NASA’s Hubble Space Telescope can resolve individual stars in the densely-packed cores of globular clusters like NGC 2210. Imagine credit: ESA/Hubble & NASA, A. Sarajedini This striking Hubble Space Telescope image shows the densely packed globular cluster known as NGC 2210, which is situated in the Large Magellanic Cloud (LMC). The LMC lies about 157,000 light-years from Earth and is a so-called satellite galaxy of the Milky Way, meaning that the two galaxies are gravitationally bound. Globular clusters are very stable, tightly bound clusters of thousands or even millions of stars. Their stability means that they can last a long time, and therefore globular clusters are often studied to investigate potentially very old stellar populations. In fact, 2017 research using some of the data that…

金字塔山上空的北斗七星

金字塔山上空的北斗七星

ByNASA中文

2023年12月10日 Big Dipper over Pyramid Mountain Image Credit & Copyright: Steve Cullen Explanation: When did you first learn to identify this group of stars? Although they are familiar to many people around the world, different cultures have associated this asterism with different icons and folklore. Known in the USA as the Big Dipper, the stars are part of a constellation designated by the International Astronomical Union in 1922 as the Great Bear (Ursa Major). The recognized star names of these stars are (left to right) Alkaid, Mizar/Alcor, Alioth, Megrez, Phecda, Merak, and Dubhe. Of course, stars in any given constellation are unlikely to be physically related. But surprisingly, most of the Big Dipper stars do seem to be headed in the same direction as they…

南峰上空的昴宿星团

南峰上空的昴宿星团

ByNASA中文

2023年12月9日 Pic du Pleiades Image Credit & Copyright: Jean-Francois Graffand Explanation: Near dawn on November 19 the Pleiades stood in still dark skies over the French Pyrenees. But just before sunrise a serendipitous moment was captured in this single 3 second exposure; a bright meteor streak appeared to pierce the heart of the galactic star cluster. From the camera’s perspective, star cluster and meteor were poised directly above the mountain top observatory on the Pic du Midi de Bigorre. And though astronomers might consider the Pleiades to be relatively close by, the grain of dust vaporizing as it plowed through planet Earth’s upper atmosphere actually missed the cluster’s tight grouping of young stars by about 400 light-years. While recording a night sky timelapse series, the…

织女星与彗星12P/庞士-布鲁克斯

织女星与彗星12P/庞士-布鲁克斯

ByNASA中文

2023年12月8日 Vega and Comet 12P/Pons-Brooks Image Credit & Copyright: Dan Bartlett Explanation: On December 4, periodic Comet 12P/Pons-Brooks shared this telescopic field of view with Vega, alpha star of the northern constellation Lyra. Fifth brightest star in planet Earth’s night, Vega is some 25 light-years distant while the much fainter comet was about 21 light-minutes away. In recent months, outbursts have caused dramatic increases in brightness for Pons-Brooks though. Nicknamed the Devil Comet for its hornlike appearance, fans of interstellar spaceflight have also suggested the distorted shape of this comet’s large coma looks like the Millenium Falcon. A Halley-type comet, 12P/Pons-Brooks last visited the inner Solar System in 1954. Its next perihelion passage or closest approach to the Sun will be April 21, 2024. That’s…

阿尔忒弥斯二号任务机组人员SLS之旅

阿尔忒弥斯二号任务机组人员SLS之旅

ByNASA中文

On Nov. 16, 2023, NASA astronauts Reid Wiseman (left) and Christina Koch (middle) of NASA and CSA (Canadian Space Agency) astronaut Jeremy Hansen (second from left) view the core stage for the Space Launch System (SLS) rocket at NASA’s Michoud Assembly Facility in New Orleans. The three astronauts, along with NASA’s Victor Glover, will launch atop the rocket stage to venture around the Moon on Artemis II, the first crewed flight for Artemis. The astronauts’ visit to Michoud coincided with the first anniversary of the launch of Artemis I. The uncrewed flight test of SLS and Orion was the first in a series of increasingly complex missions for Artemis as the agency works to return humans to the lunar surface and develop a long-term presence…

猎户座与风暴洋

猎户座与风暴洋

ByNASA中文

2023年12月7日 Orion and the Ocean of Storms Image Credit: NASA, Artemis 1 Explanation: On December 5, 2022, a camera on board the uncrewed Orion spacecraft captured this view as Orion approached its return powered flyby of the Moon. Beyond one of Orion’s extended solar arrays lies dark, smooth, terrain along the western edge of the Oceanus Procellarum. Prominent on the lunar nearside Oceanus Procellarum, the Ocean of Storms, is the largest of the Moon’s lava-flooded maria. The lunar terminator, shadow line between lunar night and day, runs along the left of this frame. The 41 kilometer diameter crater Marius is top center, with ray crater Kepler peeking in at the edge, just right of the solar array wing. Kepler’s bright rays extend to the north…

25年前: 国际空间站的第一批部件

25年前: 国际空间站的第一批部件

ByNASA中文

The mated Russian-built Zarya (left) and U.S.-built Unity modules are backdropped against the blackness of space and Earth’s horizon shortly after leaving Endeavour’s cargo bay on Dec. 13, 1998. A few days earlier, on Dec. 6, 1998, the space shuttle Endeavour, mission STS-88, launched from NASA’s Kennedy Space Center in Florida carrying the Unity connecting module and two pressurized mating adapters. The same day, the STS-88 crew captured the Russian Zarya module, launched Nov. 20, and mated it with the Unity node. Unity was the first piece of the International Space Station provided by the United States. The components in the current space station were built in various countries around the world, with each piece performing once connected in space by complex robotics systems and…

船底座的恒星与尘埃之战

船底座的恒星与尘埃之战

ByNASA中文

2023年12月6日 Stars Versus Dust in the Carina Nebula Image Credit: NASA, ESA, Hubble Heritage (STScI/AURA); Processing: Franco Meconi (Terraza al Cosmos) Explanation: It’s stars versus dust in the Carina Nebula and the stars are winning. More precisely, the energetic light and winds from massive newly formed stars are evaporating and dispersing the dusty stellar nurseries in which they formed. Located in the Carina Nebula and inside a region known informally as Mystic Mountain, these pillars’ appearance is dominated by opaque brown dust even though it is composed mostly of clear hydrogen gas. Even though some of the dust pillars look like torches, their ends are not on fire — rather, they are illuminated by nearby stars. About 7,500 light-years distant, the featured image was taken…