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ScienceDaily: Space & Time News |
Hydrogen-burning white dwarfs enjoy slow aging Posted: 06 Sep 2021 08:13 AM PDT Could dying stars hold the secret to looking younger? New evidence suggests that white dwarfs could continue to burn hydrogen in the final stages of their lives, causing them to appear more youthful than they actually are. This discovery could have consequences for how astronomers measure the ages of star clusters. |
Astronomers explain origin of elusive ultradiffuse galaxies Posted: 06 Sep 2021 08:13 AM PDT As their name suggests, ultradiffuse galaxies, or UDGs, are dwarf galaxies whose stars are spread out over a vast region, resulting in extremely low surface brightness, making them very difficult to detect. An international team of astronomers reports it has used sophisticated simulations to detect a few 'quenched' UDGs in low-density environments in the universe. A quenched galaxy is one that does not form stars. |
Risk from solar flares to planes is real but not worth costly mitigation Posted: 02 Sep 2021 09:50 AM PDT Aviation guidelines aim to mitigate the effects of radiation, mainly caused by galactic cosmic rays and solar energetic particles, or SEP. The fluxes in the former are stable and predictable: dose rates are no higher than 10 µSv/h at the normal flight altitude of 12 km. But in the case of SEP, does the frequency of detected solar flares justify the costs of countermeasures? Current mitigation procedures instruct planes to lower altitude or change or cancel flight paths altogether, significantly raising expenses. |
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