Astronauts Talking About Viewing The Earth From The Moon, From The Overview Effect: Awe And Self-Transcendent

NASA’s Most Shocking Image

This image is a 1.5… *BILLION* pixel photograph of the Andromeda Galaxy.

To view the image in all its glory go here.

NASA is the coolest thing that’s ever happened.

Rose-Colored storm on Jupiter captured by Juno spacecraft [1080 x 758]

What Happened to Mars?

Billions of years ago, Mars was a very different world. Liquid water flowed in long rivers that emptied into lakes and shallow seas. A thick atmosphere blanketed the planet and kept it warm.

Today, Mars is bitter cold. The Red Planet’s thin and wispy atmosphere provides scant cover for the surface below.

Our MAVEN Mission

The Mars Atmosphere and Volatile EvolutioN (MAVEN) mission is part of our Mars Scout program. This spacecraft launched in November 2013, and is exploring the Red Planet’s upper atmosphere, ionosphere and interactions with the sun and solar wind.

The purpose of the MAVEN mission is to determine the state of the upper atmosphere of Mars, the processes that control it and the overall atmospheric loss that is currently occurring. Specifically, MAVEN is exploring the processes through which the top of the Martian atmosphere can be lost to space. Scientists think that this loss could be important in explaining the changes in the climate of Mars that have occurred over the last four billion years.

New Findings

Today, Nov. 5, we will share new details of key science findings from our ongoing exploration of Mars during a news briefing at 2 p.m. EDT. This event will be broadcast live on NASA Television. Have questions? Use #askNASA during the briefing.

Make sure to follow us on Tumblr for your regular dose of space: http://nasa.tumblr.com 

Stellar Winds

Stellar winds are fast moving flows of material (protons, electrons and atoms of heavier metals) that are ejected from stars. These winds are characterised by a continuous outflow of material moving at speeds anywhere between 20 and 2,000 km/s.

In the case of the Sun, the wind ‘blows’ at a speed of 200 to 300 km/s from quiet regions, and 700 km/s from coronal holes and active regions.

The causes, ejection rates and speeds of stellar winds vary with the mass of the star. In relatively cool, low-mass stars such as the Sun, the wind is caused by the extremely high temperature (millions of degrees Kelvin) of the corona.

his high temperature is thought to be the result of interactions between magnetic fields at the star’s surface, and gives the coronal gas sufficient energy to escape the gravitational attraction of the star as a wind. Stars of this type eject only a tiny fraction of their mass per year as a stellar wind (for example, only 1 part in 1014 of the Sun’s mass is ejected in this way each year), but this still represents losses of millions of tonnes of material each second. Even over their entire lifetime, stars like our Sun lose only a tiny fraction of 1% of their mass through stellar winds.

In contrast, hot, massive stars can produce stellar winds a billion times stronger than those of low-mass stars. Over their short lifetimes, they can eject many solar masses (perhaps up to 50% of their initial mass) of material in the form of 2,000 km/sec winds.

These stellar winds are driven directly by the radiation pressure from photons escaping the star. In some cases, high-mass stars can eject virtually all of their outer envelopes in winds. The result is a Wolf-Rayet star.

Stellar winds play an important part in the chemical evolution of the Universe, as they carry dust and metals back into the interstellar medium where they will be incorporated into the next generation of stars. 

source (read more) + Wolf–Rayet star

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

M51, the Whirlpool Galaxy [3450 x 3697]

The Carina Nebula - A Birthplace Of Stars

The Carina Nebula lies at an estimated distance of 6,500 to 10,000 light years away from Earth in the constellation Carina. This nebula is one of the most well studied in astrophysics and has a high rate of star formation. The star-burst in the Carina region started around three million years ago when the nebula’s first generation of newborn stars condensed and ignited in the middle of a huge cloud of cold molecular hydrogen. Radiation from these stars carved out an expanding bubble of hot gas. The island-like clumps of dark clouds scattered across the nebula are nodules of dust and gas that are resisting being eaten away by photons (particles of light) that are ionizing the surrounding gas (giving it an electrical charge).

Credit: NASA/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.

Light from Cygnus A: Celebrating astronomy in this International Year of Light, the detailed image reveals spectacular active galaxy Cygnus A in light across the electromagnetic spectrum. Incorporating X-ray data extends to either side along the same axis for nearly 300,000 light-years powered by jets of relativistic particles emanating from the galaxys central supermassive black hole. Hot spots likely mark the ends of the jets impacting surrounding cool, dense material. Confined to yellow hues, optical wavelength data of the galaxy from Hubble and the surrounding field in the Digital Sky Survey complete a remarkable multiwavelength view. via NASA

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The icy blue wings of Hen 2-437

The patterns and symmetries in space never cease to amaze. Hen 2-437 is a planetary nebula which has spectacularly symmetrical wings. It was first identified in 1946 by Rudolph Minkowski, who later also discovered the famous and equally beautiful M2-9, otherwise known as the Twin Jet Nebula:

Hen 2-437 was added to a catalogue of planetary nebula over two decades later by astronomer and NASA astronaut Karl Gordon Henize. If you’re interested in how planetary nebulae form, go here

Credit: ESA/Hubble & NASA