2025 December 30

An Artificial Comet
* Image Credit & Copyright: Wang Chao
https://en.tutiempo.net/astronomy/astronomical-view/wang-chao.html

Explanation:
Yes, but can your comet tail do this? No, and what you are seeing is not the tail of a comet. The picture features a cleverly overlayed time-lapse sequence of a group of satellites orbiting Earth together in June. Specifically, these are Starlink communications satellites in low Earth orbit reflecting back sunlight before sunrise to Inner Mongolia, China. Although the satellites appear to the human eye as points, the 20-second-long camera exposures caused them to appear as short streaks. Currently there are over 9000 (!) + Starlinks in orbit, with more being launched nearly every week.
Other satellite constellations are also being planned.

+ Note grobi: "Sorry, but I refuse to link Starlink pages and thus advertise for companies or platforms of a fascist"

https://apod.nasa.gov/apod/ap251230.html

#space #astronomy #science #physics #astrophotography #photography #nature #NASA #apod #space_related #space_culture_Club

2025 December 29

M1: The Crab Nebula
* Image Credit & Copyright: Alan Chen
https://www.heavenlyview.com/about.htm

Explanation:
This is the mess that is left when a star explodes. The Crab Nebula, the result of a supernova seen in 1054 AD, is filled with mysterious filaments. The filaments are not only tremendously complex but appear to have less mass than expelled in the original supernova and a higher speed than expected from a free explosion. The featured image was taken by an amateur astronomer in Leesburg, Florida, USA over three nights last month. It was captured in three primary colors but with extra detail provided by specific emission by hydrogen gas. The Crab Nebula spans about 10 light years. In the Nebula's very center lies a pulsar: a neutron star as massive as the Sun but with only the size of a small town. The Crab Pulsar rotates about 30 times each second.
https://science.nasa.gov/mission/hubble/science/explore-the-night-sky/hubble-messier-catalog/messier-1/
https://spaceplace.nasa.gov/supernova/en/
http://www.messier.seds.org/more/m001_sn.html
https://www.youtube.com/watch?v=5VnJ9pRR8-8
https://apod.nasa.gov/apod/ap980208.html
https://ui.adsabs.harvard.edu/abs/1995ApJ...454L.129F/abstract
https://ui.adsabs.harvard.edu/abs/1998PASP..110..831N/abstract
https://en.wikipedia.org/wiki/RGB_color_model
https://en.wikipedia.org/wiki/Hydrogen-alpha
https://spinoff.nasa.gov/NASA_Hydrogen_History_Informs_World%E2%80%99s_Hydrogen_Future
https://en.wikipedia.org/wiki/Crab_Nebula
https://science.nasa.gov/exoplanets/what-is-a-light-year/
https://www.planetary.org/space-images/comet-67p-compared-to-los-angeles
https://apod.nasa.gov/apod/ap020920.html
https://defcon.social/@grobi/115081987454568071
https://defcon.social/@grobi/114793535752274563

https://apod.nasa.gov/apod/ap251229.html

#space #nebula #astrophotography #photography #science #astronomy #physics #nature #NASA #apod