Contributor Posts

NASA Astronomy Picture of the Day:

The interstellar cloud of dust and gas captured in this sharp telescopic snapshot is seen to change its appearance noticeably over periods as short as a few weeks. Discovered over 200 years ago and cataloged as NGC 2261, bright star R Monocerotis lies at the tip of the fan-shaped nebula. About one light-year across and 2500 light-years away, NGC 2261 was studied early last century by astronomer Edwin Hubble and the mysterious cosmic cloud is now more famous as Hubble's Variable Nebula. So what makes Hubble's nebula vary? NGC 2261 is composed of a dusty reflection nebula fanning out from the star R Monocerotis. The leading variability explanation holds that dense knots of obscuring dust pass close to R Mon and cast moving shadows across the dust clouds in the rest of Hubble's Variable Nebula.

Photo by Tommy Lease

A juvenile green iguana (Iguana iguana) in Brejo da Madre de Deus, Pernambuco, Brazil.

KarlaFPaiva, CC BY-SA 3.0, via Wikimedia Commons. View source.

NASA Astronomy Picture of the Day:

Gorgeous spiral galaxy Messier 33 seems to have more than its fair share of glowing hydrogen gas. A prominent member of the local group of galaxies, M33 is also known as the Triangulum Galaxy and lies a mere 3 million light-years away. The galaxy's central 60,000 light-years or so are shown in this sharp galaxy portrait. The portrait features M33's reddish ionized hydrogen clouds or HII regions. Sprawling along loose spiral arms that wind toward the core, M33's giant HII regions are some of the largest known stellar nurseries, sites of the formation of short-lived but very massive stars. Intense ultraviolet radiation from the luminous, massive stars ionizes the surrounding hydrogen gas and ultimately produces the characteristic red glow. In this image, broadband data were combined with narrowband data recorded through a filter that transmits the light of the strongest visible hydrogen and oxygen emission lines.

Photo by Pea Mauro

The Bhaga river flowing from Darcha in the distance down past Jispa. Stunted juniper growing on the lower slopes. View from above Gemur Gompa. Elevations: river 3,250 m (10,660 ft), peaks 5,200–5,700 m (17,100–18,700 ft). Lahaul, Himachal Pradesh, India.

This Photo was taken by Timothy A. Gonsalves. Feel free to use my photos, but please mention me as the author. I would much appreciate if you send me an email tagooty@gmail.com or write on my talk page, for my information. Please contact me before commercial use. Please do not upload an edited image here without consulting me. I would like to make corrections only at my own source to ensure that the changes improve the image and are preserved.Otherwise you may upload an edited image with a new name. Please use one of the templates derivative or extract., CC BY-SA 4.0, via Wikimedia Commons. View source.

NASA Astronomy Picture of the Day:

What are those strange rings? Rich in dust, the rings are likely 3D shells -- but how they were created remains a topic of research. Where they were created is well known: in a binary star system that lies about 6,000 light years away toward the constellation of the Swan (Cygnus) -- a system dominated by the Wolf-Rayet star WR 140. Wolf-Rayet stars are massive, bright, and known for their tumultuous winds. They are also known for creating and dispersing heavy elements such as carbon, which is a building block of interstellar dust. The other star in the binary is also bright and massive -- but not as active. The two great stars joust in an oblong orbit as they approach each other about every eight years. When at closest approach, the X-ray emission from the system increases, as, apparently, does the dust expelled into space -- creating another shell. The featured infrared image by the Webb Space Telescope resolves greater details and more dust shells than ever before. Images taken over consecutive years show the shells moving outward.

A botanical diagram of a typical grass plant.

Kelvinsong, CC BY 3.0, via Wikimedia Commons. View source.

NASA Astronomy Picture of the Day:

Comets can be huge. When far from the Sun, a comet's size usually refers to its hard nucleus of ice and rock, which typically spans a few kilometers -- smaller than even a small moon. When nearing the Sun, however, this nucleus can eject dust and gas and leave a thin tail that can spread to an enormous length -- even greater than the distance between the Earth and the Sun. Pictured, C/2024 G3 (ATLAS) sports a tail of sunlight-reflecting dust and glowing gas that spans several times the apparent size of a full moon, appearing even larger on long duration camera images than to the unaided eye. The featured image shows impressive Comet ATLAS over trees and a grass field in Sierras de Mahoma, San Jose, Uruguay about a week ago. After being prominent in the sunset skies of Earth's southern hemisphere, Comet G3 ATLAS is now fading as it moves away from the Sun, making its impressive tails increasingly hard to see. Gallery: Comet ATLAS (G3)

Photo by Mauricio Salazar

Breakwaters in Sarbinowo by the Bay of Pomerania. West Pomeranian Voivodeship, Poland.

Łukasz Śmigasiewicz, CC BY-SA 3.0 pl, via Wikimedia Commons. View source.