The 'baritone' of red giants refines cosmic distance measurements
A fresh look at red giant stars offers key insights into cosmic distance measurements and a way to measure the universe's expansion with the highest accuracy.
A fresh look at red giant stars offers key insights into cosmic distance measurements and a way to measure the universe's expansion with the highest accuracy.
Astronomy
Mar 15, 2024
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100
A critical molecule for the metabolism of living organisms has been synthesized for the first time by University of Hawaiʻi at Mānoa researchers at low temperatures (10 K) on ice coated nanoparticles mimicking conditions ...
Astrobiology
Mar 13, 2024
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A groundbreaking study of the origins of intermediate-velocity clouds (IVCs) challenges a 20-year-old theory and suggests a new era of deep-space research.
Astronomy
Mar 11, 2024
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33
An international team of researchers, including a scientist at The New York Botanical Garden (NYBG), has documented and described seven rare new plant species with brightly colored flowers that are only found in highly threatened ...
Plants & Animals
Mar 7, 2024
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12
A galaxy that suddenly stopped forming new stars more than 13 billion years ago has been observed by astronomers.
Astronomy
Mar 6, 2024
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After 16 years studying Earth's highest clouds for the benefit of humanity—polar mesospheric clouds—from its orbit some 350 miles above the ground, NASA's Aeronomy of Ice in the Mesosphere, or AIM, mission has come to ...
Space Exploration
Mar 1, 2024
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31
Central Asia has experienced a faster temperature rise than the global land over the past decades, which has brought unprecedented challenges to the survival and flourishing of life. The role of the drivers and their associated ...
Earth Sciences
Feb 29, 2024
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12
Using NASA's Chandra X-ray spacecraft, astronomers have inspected a potential super-star cluster, designated HSO BMHERICC J72.971176-69.391112, or H72.97−69.39 for short. The new observations resulted in the detection of ...
In July of 2023, retired commander in the U.S. Navy David Fravor testified to the House Oversight Committee about a mysterious, Tic Tac-shaped object that he and three others observed over the Pacific Ocean in 2004. The congressional ...
Space Exploration
Feb 28, 2024
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79
An international team of astronomers has used the James Webb Space Telescope (JWST) to conduct mid-infrared observations of a nearby supernova known as SN 1987A. Results of the observational campaign, published February 21 ...
A cloud is a visible mass of droplets or frozen crystals suspended in the atmosphere above the surface of the Earth or another planetary body. A cloud is also a visible mass attracted by gravity, such as masses of material in space called interstellar clouds and nebulae. Clouds are studied in the nephology or cloud physics branch of meteorology.
On Earth the condensing substance is typically water vapor, which forms small droplets or ice crystals, typically 0.01 mm in diameter. When surrounded by billions of other droplets or crystals they become visible as clouds. Dense deep clouds exhibit a high reflectance (70% to 95%) throughout the visible range of wavelengths. They thus appear white, at least from the top. Cloud droplets tend to scatter light efficiently, so that the intensity of the solar radiation decreases with depth into the gases, hence the gray or even sometimes dark appearance at the base. Thin clouds may appear to have acquired the color of their environment or background and clouds illuminated by non-white light, such as during sunrise or sunset, may appear colored accordingly. In the near-infrared range, clouds look darker because the water that constitutes the cloud droplets strongly absorbs solar radiation at those wavelengths.
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