“One such region, NGC 6357, is a huge nebula that radiates brightly in many different wavelengths. The infrared highlights the warm gas that’s heated by new stars, while the “dark gaps” are where the intense ultraviolet radiation has ionized and evaporated the gas away. The neutral gas also reflects visible light, highlighting its fragmented, filamentary structure.”
The Lobster Nebula seen with ESO’s VISTA telescope
This image from ESO’s VISTA telescope captures a celestial landscape of vast, glowing clouds of gas and tendrils of dust surrounding hot young stars. This infrared view reveals the stellar nursery known as NGC 6357 in a new light. It was taken as part of the VISTA Variables in the Vía Láctea (VVV) survey, which is currently scanning the Milky Way in a bid to map our galaxy’s structure and explain how it formed.
The Omega Nebula, also known as the Swan Nebula, Checkmark Nebula, Lobster Nebula, and the Horseshoe Nebula (catalogued as Messier 17 or M17 and as NGC 6618) is an H II region in the constellation Sagittarius. It was discovered by Philippe Loys de Chéseaux in 1745. Charles Messier catalogued it in 1764. It is located in the rich starfields of the Sagittarius area of the Milky Way.
The Omega Nebula is between 5,000 and 6,000 light-years from Earth and it spans some 15 light-years in diameter. The cloud of interstellar matter of which this nebula is a part is roughly 40 light-years in diameter and has a mass of 30,000 solar masses. The total mass of the Omega Nebula is an estimated 800 solar masses.
It is considered one of the brightest and most massive star-forming regions of our galaxy. Its local geometry is similar to the Orion Nebula except that it is viewed edge-on rather than face-on.
An open cluster of 35 stars lies embedded in the nebulosity and causes the gases of the nebula to shine due to radiation from these hot, young stars; however the actual number of stars in the nebula is much higher - up to 800, plus >1000 stars in formation on its outer regions.It’s also one of the youngest clusters known, with an age of just 1 million years.