杏吧原创

Universe

Space

What we know about the stars where NASA will hunt for alien life

杏吧原创s have analysed the stars that an upcoming NASA telescope will target in its search for biosignatures, narrowing down the candidates for those that could host potential extraterrestrial life

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Wolf-Rayet stars are known to be efficient dust producers, and the Mid-Infrared Instrument (MIRI) on NASA?s James Webb Space Telescope shows this to great effect. Cooler cosmic dust glows at the longer mid-infrared wavelengths, displaying the structure of WR 124?s nebula. The nebula is made of material cast off from the aging star in random ejections, and from dust produced in the ensuing turbulence. This brilliant stage of mass loss precedes the star?s eventual supernova, when nuclear fusion in its core stops and the pressure of gravity causes it to collapse in on itself, and then explode. As MIRI demonstrates here, Webb will help astronomers to explore questions that were previously only left to theory about how much dust stars like this create before exploding in a supernova, and how much of that dust is large enough to survive the blast and go on to serve as building blocks of future stars and planets.

Space

How galactic mysteries near and far are poised to shake up cosmology

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Artist's impression of the path the fast radio burst FRB 20220610A took between the distant galaxy where it originated and Earth, in one of the Milky Way's spiral arms (not to scale)

Space

A blast of radio waves hit Earth after travelling for 8 billion years

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S3F98G Colorful balloons against the light

Space

How the balloon analogy for an expanding universe is almost perfect

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Herbig-Haro 46/47, captured by NASA's James Webb Space Telescope

Space

JWST should soon glimpse the very first stars born after the big bang

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Space

How the end of the universe was completely rewritten

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The universe gets clumpier over time

Space

The universe鈥檚 evolution seems to be slowing and we don鈥檛 know why

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What looks much like craggy mountains on a moonlit evening is actually the edge of a nearby, young, star-forming region NGC 3324 in the Carina Nebula. Captured in infrared light by the Near-Infrared Camera (NIRCam) on NASA???s James Webb Space Telescope, this image reveals previously obscured areas of star birth. Called the Cosmic Cliffs, the region is actually the edge of a gigantic, gaseous cavity within NGC 3324, roughly 7,600 light-years away. The cavernous area has been carved from the nebula by the intense ultraviolet radiation and stellar winds from extremely massive, hot, young stars located in the center of the bubble, above the area shown in this image. The high-energy radiation from these stars is sculpting the nebula???s wall by slowly eroding it away. NIRCam ??? with its crisp resolution and unparalleled sensitivity ??? unveils hundreds of previously hidden stars, and even numerous background galaxies. Several prominent features in this image are described below. ??? The ???steam??? that appears to rise from the celestial ???mountains??? is actually hot, ionized gas and hot dust streaming away from the nebula due to intense, ultraviolet radiation. ??? Dramatic pillars rise above the glowing wall of gas, resisting the blistering ultraviolet radiation from the young stars. ??? Bubbles and cavities are being blown by the intense radiation and stellar winds of newborn stars. ??? Protostellar jets and outflows, which appear in gold, shoot from dust-enshrouded, nascent stars. ??? A ???blow-out??? erupts at the top-center of the ridge, spewing gas and dust into the interstellar medium. ??? An unusual ???arch??? appears, looking like a bent-over cylinder. This period of very early star formation is difficult to capture because, for an individual star, it lasts only about 50,000 to 100,000 years ??? but Webb???s extreme sensitivity and exquisite spatial resolution have chronicled this rare event. Located roughly 7,600 light-years away, NGC 3324 was first cat

Space

The JWST is already delivering on its promise to transform cosmology

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2NMX51D This satellite image provided by the National Oceanic and Atmospheric Administration (NOAA) shows a tropical storm east of Puerto Rico in the Caribbean, at 7:50am EST, Tuesday, Aug. 10, 2021. The National Hurricane Center issued tropical storm warnings for the U.S. Virgin Islands and Puerto Rico, where forecasters expected the potential cyclone to strengthen Tuesday into the sixth named storm, Fred, of the Atlantic hurricane season. (NOAA/NESDIS/STAR GOES via AP)

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The Universe in a Box review: Why all cosmic quests start on laptops

Culture

Space

What the huge young galaxies seen by JWST tell us about the universe

A few months ago, the James Webb Space Telescope spotted six early galaxies that were so large they threatened to break our best theory of how the cosmos evolved. Did they?

Features

Space

Questions I dread: How did the universe begin, and what is space-time?

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Physics

Can recreating black holes in the lab solve the puzzles of space-time?

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Physics

Why darkness between stars reveals more about the universe than light

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Physics

Do we live in a hologram? Why physics is still mesmerised by this idea

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