NASA Hubble Space Telescope Images (via Hubble Heritage)
IC 4406: A Seemingly Square Nebula
Credit: C. R. O’Dell (Vanderbilt U.) et al., Hubble Heritage Team, NASA
The Carina nebula is a sprawling, monstrous complex of gas located a mere 7500 light years from Earth. Hundreds of light years across, it’s massive enough to create thousands of stars like the Sun. Tens of thousands.
And churn out stars it does. Embedded in the nebula are several clusters of newborn stars, and many of these stars are so massive they’re nearly at the limit of how big a star can be without tearing itself apart. Stars that big explode as supernovae, and a new mosaic by the orbiting Chandra X-ray Observatory indicate they’ve been popping off in the nebula for quite some time
Image credits: NASA/CXC; Digitized Sky Survey/CXC
The image shows the Jellyfish Nebula or IC443 to the right, and IC444 to the the left. The first is a planetary nebula which shelters a neutron star, the product of a star that exploded about 30,000 years ago and left a very large remnant; it is located about 5,000 light years away. In the picture the nebulae are flanked by the stars Mu and Etas in the constellation Gemini.
When the word nebula entered English in the early 15th century, it had nothing to do with astronomy. Arriving as nebule meaning a cloud or mist from the Latin word nebula meaning mist, which in turn came from the Proto Indo-European root word *nebh-meaning cloud, vapor, fog, moist, sky. Ancient Greek had the related word nephele, nephos which also meant cloud. When the word nebula reappeared in English it had a medical meaning for cataracts or cloudy defects in the eye. The astronomical meaning of a cloud-like patch in the night sky was first recorded around 1730. It wasn’t until the early 20th century with the advent of modern and powerful telescopes that nebula were fully understood as massive clouds of gas and dust.
Image of the Bubble nebula, the Carina Nebula, the Lagoon Nebula and the 30 Doradus nebula, all courtesy NASA from Hubble Space Telescope Program.
A Messier Object is an astronomical object first described by the great French astronomer Charles Messier in 1771. An insatiable comet hunter, Messier began his catalog of objects that were neither stars nor comets as a way of accounting for them and subsequently avoiding them as he searched for comets. With the help of his assistant Pierre Méchain, the first edition of the Catalogue des Nébuleuses et des Amas d’Étoiles (Catalogue of Nebulae and Star Clusters) contained 45 objects, mostly nebulae, galaxies and star clusters. According to Messier, who was waiting for the return of Halley’s Comet:
What caused me to undertake the catalog was the nebula I discovered above the southern horn of Taurus on September 12, 1758, whilst observing the comet of that year. This nebula had such a resemblance to a comet in its form and brightness that I endeavored to find others, so that astronomers would no more confuse these same nebulae with comets just beginning to appear.
Messier’s final publication included 103 objects, but the catalog was added to as recently as 1966, almost 200 years after his original publication! Today the catalog contains 110 objects and many objects are still referred to by their Messier number.
All images in the public domain, courtesy NASA.
LL Ori and the Orion Nebula
Credit: NASA, ESA, and The Hubble Heritage Team
Merope’s Reflection Nebula
Image Credit & Copyright: Leonardo Orazi
AE Aurigae and the Flaming Star Nebula
Credit & Copyright: Jorge Garcia
X-Rays from the Cat’s Eye Nebula
Credit: X-ray: NASA/CXC/SAO; Optical: NASA/STScI
In the Center of the Trifid Nebula
Credit & Copyright: Daniel Lopez