Asteroid (6478) Gault

This isn’t a comet. It’s Asteroid (6478) Gault out in the main belt between Mars and Jupiter. So what’s it doing with a pair of tails? The longer tail stretches more than 800,000 km) and is roughly 4,800 km wide. The shorter one is roughly a quarter as long.

One theory suggests that the tiny asteroid, only 2.5 miles wide, is disintegrating as a result of long-term effects of sunlight. Sunlight? Yes, the cumulative force of the Sun’s light can slowly speed up a small body’s spin, and when spinning fast enough, it will throw off material. Pressure from sunlight very slowly began spinning up the diminutive asteroid at an estimated rate of 1 second every 10,000 years, the it may have taken 100 million years or so to get the spin rate up to a destructive level.

Image Credit: NASA

The Ghost Nebula

The Ghost Nebula (aka IC 63) is located 550 light-years away in the constellation Cassiopeia the Queen. The nebula’s glow reminds some people of the apparitions reported by paranormal investigators. In reality, it’s simply radiation from hydrogen that is being bombarded with ultraviolet light by the nearby blue-giant star Gamma Cassiopeiae (not seen in this picture). The blue light is starlight reflected by the nebula’s dust.

Image Credit: NASA / ESA

Billions and Billions

Over 200 billion. Stars that is. This fuzzy blob of light is the galaxy known as Messier 49 (or M49). It’s a giant elliptical galaxy with 200 billion stars. Spiral galaxies have a well-defined structure with spiral arms, but elliptical galaxies are fairly smooth and lack obvious features. M49 was the first member of the Virgo Cluster of galaxies to be discovered, and it is more luminous than any other galaxy at its distance (56 million light-years) or nearer. It is about 157,000 light-years across.

Image Credit: NASA / ESA

The Crab Nebula

In 1054, observers around the world reported the appearance of a “new star” in the direction of the constellation Taurus. The remnant of that supernova is called the Crab Nebula, and it is powered by a quickly spinning, highly magnetized neutron star called a pulsar. The pulsar was formed when the massive star ran out of its nuclear fuel and collapsed. The combination of rapid rotation and a strong magnetic field in the Crab generates an intense electromagnetic field that creates jets of matter and anti-matter moving away from both the north and south poles of the pulsar and an intense wind flowing out in the equatorial direction.

This composite image of the nebula was created with data from the Chandra X-ray Observatory (blue and white), the Hubble Space Telescope (purple), and the Spitzer Space Telescope (pink).

Image Credit: NASA

An Eye in the Sky

ngc6751_hst_960Planetary nebulae appear simple, round, and planet-like in small telescopes. However, images from the Hubble Space Telescope have become well known for showing these fluorescent gas shrouds of dying Sun-like stars to possess a staggering variety of detailed symmetries and shapes. This composite color Hubble image of NGC 6751, the Glowing Eye Nebula, is a lovely example of a complex planetary nebula. Winds and radiation from the intensely hot central star (140,000 °C) have created the nebula’s streamer-like features. The nebula is about 0.8 light-years across, roughly 600 times the diameter of our Solar System. It’s 6,500 light-years distant in the constellation Aquila (the Eagle).

Image Credit: NASA