NGC 6302- The Butterfly Nebula

Cosmic Fireworks

Like an incredible celestial firework display, dust, ionized material and molecular gas from a dying star form the Helix Nebula. The star is evolving to become a white dwarf star and appears as the tiny blue dot seen at the center. This picture, taken in infrared light by the ESO’s VISTA telescope at the Paranal Observatory, reveals strands of cold nebular gas that is invisible in images taken in visible light. The main ring of the Helix is about two light-years across, roughly half the distance between the Sun and the nearest star. Material from the nebula spreads out from the star to at least four light-years. The Helix Nebula lies in the constellation of Aquarius about 700 light years from Earth. (Credit: ESO)

Where Could Life Exist?

When NASA scientists announced earlier this year that they had found evidence of liquid water on Mars, imaginations ran wild with the possibility that life could exist somewhere other than here on Earth.

Scientists continue to explore the possibility that Mars once looked a lot like Earth — salty oceans, fresh water lakes, and a water cycle to go with it. That’s exciting stuff.

So where else are they looking? What exactly are they looking for?

There are nine places in our universe where scientists say life is a possibility. The locations range from a smoking hot planet like Venus to a moon that orbits Saturn called Enceladus, which looks a lot like a massive, tightly-packed ball of ice.

All of these places show signs that water is, or at least was, a possibility. They also appear to feature some kind of energy that could produce heat.

full resolution

This photograph of Neptune was reconstructed from two images taken by Voyager 2’s narrow-angle camera, through the green and clear filters. At the north (top) is the Great Dark Spot, accompanied by bright, white clouds that undergo rapid changes in appearance.

Credit: NASA

Antennae galaxies, an intense star-forming region created when two galaxies began to collide some 200 million to 300 million years ago. The bright, blue-white areas show newly formed stars surrounded by clouds of hydrogen, which are colored pink. A similar collision is expected between our galaxy, the Milky Way, and the nearby Andromeda galaxy in several billion years.

Source: national geographic

Credit:NASA/ESA/HUBBLE

Black holes

             Perseus Black hole                

                   Black holes are objects that have collapsed under their own weight to a point, creating an object that is very small but enormously dense. It is a region of space that has a gravitational pull so strong that no imminent particle or electromagnetic radiation can escape from it. This astonishing concept of black hole was first given by John Michell in 1783.He proposed that if you take the sun and compress it to a very small volume it would have a gravitational pull so strong that you have to travel at speeds greater than the speed of light to escape it.At first black holes are thought to be theoretical concepts which do not exist. But later they turned out to be very real. So how do these giant suckers form?

                 In order to understand the formation of a black hole we need to understand the formation and the life cycle of stars. A star is formed when large amounts of dust and gases, mainly hydrogen gas condense and collapse under its own gravitational force. As the gas collapses, the atoms of the gas collide with each other at higher and higher speeds resulting in the heating of the gas. Ultimately the gas becomes so hot that when the hydrogen atoms collide they don’t bounce off, but fuse together to form helium atoms, same as in the hydrogen bomb. As a result a large amount of heat is released which is the reason why stars shine. This heat increases the pressure of the gas until it balances out the gravitational pull and the gas stops contracting. Hence a star is formed.

     The stars are usually stable as long as they have hydrogen in them. As the hydrogen runs out, the fusion reaction stops. To keep the fusion reaction going the star turns to its helium reserve. After it runs out of helium, it switches to carbon, and then oxygen. Stars with the mass of our Sun stop at this point as they don’t have enough energy to continue the fusion process and become white dwarfs. But stars with about 5 times the mass of our sun continue further to produce silicon, aluminum, potassium so on up to iron. No further energy can be produced by fusing iron atoms so the star starts to cool down. Once the external force of radiation stops acting the gravitational pull takes over and the star begins to contract. The entire mass of the star collapses into smaller and smaller volume of space. Eventually when the star has contracted to a certain critical radius, the gravitational field at the surface becomes so strong that even light cannot escape it. And this is how a black hole is formed.

     Another way of formation of black hole is when two neutron stars collide with each other. When they collide their combined mass results in a very high gravitational force that leads to a collapse and a black hole is formed.

In this image, information from the Chandra X-ray Observatory is combined with images from the Hubble Space Telescope. NASA believes these two black holes are spiraling toward each other and have been doing so for 30 years.

Jupiter’s south pole, taken by Cassini

Image of Messier 81 (M81). Located about 12 million light-years away in the Ursa Major constellation, M81 is among the brightest of the galaxies visible by telescope from Earth.

Image credit:NASA/JPL-Caltech/ESA/Harvard-Smithsonian CfA

Spirit sends one of those pictures that looks like it could come from the red rock deserts of the American West, but actually shows part of the landscape in Gusev crater, a mere 60 million miles away. Credit: NASA

The dune field at the center of Victoria Crater, seen in a new false-color shot. Credit: NASA

stars, mercury, and solar corona, photographed by stereo a, january 2009.

27 frames, photographed over 36 hours, 2nd-3rd january. the sun is out of frame right.

image credit: nasa/stereo. animation: ageofdestruction.

Spectacular!

Credit: Fragile Oasis