The wonderful univers in that we live

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A type Ia supernova (type one-a) is a type of supernova that occurs in binary systems (two stars orbiting one another) in which one of the stars is a white dwarf. The other star can be anything from a giant star to an even smaller white dwarf.

Physically, carbon–oxygen white dwarfs with a low rate of rotation are limited to below 1.44 solar masses (M☉). Beyond this, they re-ignite and in some cases trigger a supernova explosion. Somewhat confusingly, this limit is often referred to as the Chandrasekhar mass, despite being marginally different from the absolute Chandrasekhar limit where electron degeneracy pressure is unable to prevent catastrophic collapse. If a white dwarf gradually accretes mass from a binary companion, the general hypothesis is that its core will reach the ignition temperature for carbon fusion as it approaches the limit.

However, if the white dwarf merges with another white dwarf (a very rare event), it will momentarily exceed the limit and begin to collapse, again raising its temperature past the nuclear fusion ignition point. Within a few seconds of initiation of nuclear fusion, a substantial fraction of the matter in the white dwarf undergoes a runaway reaction, releasing enough energy (1–2×1044 J) to unbind the star in a supernova explosion.

This type Ia category of supernovae produces consistent peak luminosity because of the uniform mass of white dwarfs that explode via the accretion mechanism. The stability of this value allows these explosions to be used as standard candles to measure the distance to their host galaxies because the visual magnitude of the supernovae depends primarily on the distance.

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Photo of the Day – Native to Colombia and Ecuador, the Plate-billed Mountain Toucan (Andigena laminirostris) live in the high-altitude montane forests of the Andes. It is currently listed by the IUCN as Near Threatened, and its population size continues to decline due to loss of habitat and poaching for the exotic bird trade.

Polar bears could become extinct faster than was feared, study says

Polar bears could be sliding towards extinction faster than previously feared, with the animals facing an increasing struggle to find enough food to survive as climate change steadily transforms their environment.

New research has unearthed fresh insights into polar bear habits, revealing that the Arctic predators have far higher metabolisms than previously thought. This means they need more prey, primarily seals, to meet their energy demands at a time when receding sea ice is making hunting increasingly difficult for the animals.

A study of nine polar bears over a three-year period by the US Geological Survey and UC Santa Cruz found that the animals require at least one adult, or three juvenile, ringed seals every 10 days to sustain them. Five of the nine bears were unable to achieve this during the research, resulting in plummeting body weight – as much as 20kg during a 10-day study period.

Stars are giant, luminous spheres of plasma. There are billions of them — including our own sun — in the Milky Way Galaxy. And there are billions of galaxies in the universe. So far, we have learned that hundreds also have planets orbiting them.

1. Stars are made of the same stuff

All stars begin from clouds of cold molecular hydrogen that gravitationally collapse. As they cloud collapses, it fragments into many pieces that will go on to form individual stars. The material collects into a ball that continues to collapse under its own gravity until it can ignite nuclear fusion at its core. This initial gas was formed during the Big Bang, and is always about 74% hydrogen and 25% helium. Over time, stars convert some of their hydrogen into helium. That’s why our Sun’s ratio is more like 70% hydrogen and 29% helium. But all stars start out with ¾ hydrogen and ¼ helium, with other trace elements.

2. Most stars are red dwarfs

If you could collect all the stars together and put them in piles, the biggest pile, by far, would be the red dwarfs. These are stars with less than 50% the mass of the Sun. Red dwarfs can even be as small as 7.5% the mass of the Sun. Below that point, the star doesn’t have the gravitational pressure to raise the temperature inside its core to begin nuclear fusion. Those are called brown dwarfs, or failed stars. Red dwarfs burn with less than 1/10,000th the energy of the Sun, and can sip away at their fuel for 10 trillion years before running out of hydrogen.

3. Mass = temperature = color

The color of stars can range from red to white to blue. Red is the coolest color; that’s a star with less than 3,500 Kelvin. Stars like our Sun are yellowish white and average around 6,000 Kelvin. The hottest stars are blue, which corresponds to surface temperatures above 12,000 Kelvin. So the temperature and color of a star are connected. Mass defines the temperature of a star. The more mass you have, the larger the star’s core is going to be, and the more nuclear fusion can be done at its core. This means that more energy reaches the surface of the star and increases its temperature. There’s a tricky exception to this: red giants. A typical red giant star can have the mass of our Sun, and would have been a white star all of its life. But as it nears the end of its life it increases in luminosity by a factor of 1000, and so it seems abnormally bright. But a blue giant star is just big, massive and hot.

4. Most stars come in multiples

It might look like all the stars are out there, all by themselves, but many come in pairs. These are binary stars, where two stars orbit a common center of gravity. And there are other systems out there with 3, 4 and even more stars. Just think of the beautiful sunrises you’d experience waking up on a world with 4 stars around it.

5. The biggest stars would engulf Saturn

Speaking of red giants, or in this case, red supergiants, there are some monster stars out there that really make our Sun look small. A familiar red supergiant is the star Betelgeuse in the constellation Orion. It has about 20 times the mass of the Sun, but it’s 1,000 times larger. But that’s nothing. The largest known star is the monster UY Scuti.  It is a current and leading candidate for being the largest known star by radius and is also one of the most luminous of its kind. It has an estimated radius of 1,708 solar radii (1.188×109 kilometres; 7.94 astronomical units); thus a volume nearly 5 billion times that of the Sun.

6. There are many, many stars

Quick, how many stars are there in the Milky Way. You might be surprised to know that there are 200-400 billion stars in our galaxy. Each one is a separate island in space, perhaps with planets, and some may even have life.

7. The Sun is the closest star

Okay, this one you should know, but it’s pretty amazing to think that our own Sun, located a mere 150 million km away is average example of all the stars in the Universe. Our own Sun is classified as a G2 yellow dwarf star in the main sequence phase of its life. The Sun has been happily converting hydrogen into helium at its core for 4.5 billion years, and will likely continue doing so for another 7+ billion years. When the Sun runs out of fuel, it will become a red giant, bloating up many times its current size. As it expands, the Sun will consume Mercury, Venus and probably even Earth. 

8. The biggest stars die early

Small stars like red dwarfs can live for trillions of years. But hypergiant stars, die early, because they burn their fuel quickly and become supernovae. On average, they live only a few tens of millions of years or less.

9. Failed stars

Brown dwarfs are substellar objects that occupy the mass range between the heaviest gas giant planets and the lightest stars, of approximately 13 to 75–80 Jupiter masses (MJ). Below this range are the sub-brown dwarfs, and above it are the lightest red dwarfs (M9 V). Unlike the stars in the main-sequence, brown dwarfs are not massive enough to sustain nuclear fusion of ordinary hydrogen (1H) to helium in their cores.

10. Sirius: The Brightest Star in the Night Sky

Sirius is a star system and the brightest star in the Earth’s night sky. With a visual apparent magnitude of −1.46, it is almost twice as bright as Canopus, the next brightest star. The system has the Bayer designation Alpha Canis Majoris (α CMa). What the naked eye perceives as a single star is a binary star system, consisting of a white main-sequence star of spectral type A0 or A1, termed Sirius A, and a faint white dwarf companion of spectral type DA2, called Sirius B. 

To know more click the links: white dwarf, supernova, +stars, pulsars

sources: wikipedia and universetoday.com

Center of the Lagoon Nebula 

¿Por qué no puede cada quien hacer lo que quiere sin que uno se meta en sus cosas? Como dicen: cada quien con su cada cual. Todos tenemos problemas, a todos nos pasan cosas malas y en vez de todos ayudarnos, unos se burlan, otros causan más problemas y otros se quedan callados desde lejos, mirando, atemorizados de ayudar a los demás.

¿Por qué la gente tiene esa tendencia de quererse enaltecer por las desgracias de los demás? Como me dijo una vez mi mama: si no tienes algo bueno que decir, de los que te rodean, no lo digas. Tan fácil como todos vivir en armonía, sin rencores, sin egoísmo, creando una cultura altruista, es decir, basada en hacer el bien ajeno sin esperar nada a cambio. Mi mama también me enseño el otro lado de la moneda, diciéndome: palabras necias, oídos sordos. Si alguien te dice o te hace algo malo, no le hagas caso, no dejes que te quite tu paz y tu tranquilidad interior. No seguimos en el mundo donde todo solía regirse por el “ojo por ojo, diente por diente”.

Tanto odio creado por religión, por política, por orientación sexual, por color de piel y por cultura, tanto odio que no debería existir. Por tanto del homofóbico hacia el homosexual, como del homosexual hacia el homofóbico, como del religioso hacia el ateo y del ateo hacia el religioso, como el de un color contra el otro, una cultura contra la otra. Todos somos iguales, todos somos humanos, todos comemos, sentimos, pensamos, creemos, soñamos, lloramos, reímos, todos somos parte de un mismo planeta que, se supone, debería de vivir en armonía. El hombre rico no es y nunca será más que el hombre pobre, ni el pobre será más que el hombre rico, esto es para ambas partes de la moneda.

Todos podemos hacer lo que quieran, todos podemos vivir a al manera que nos haga felices, con nuestras pasiones, con nuestros gustos, con nuestras creencias, siempre y cuando no nos metamos con la dignidad de los demás, ni ofendamos a otras personas con nuestras acciones. Tampoco se trata de abusar del poder, se trata de compartir el poder, de todos ser parte de la misma canción. Somos una especia magnifica, maravillosa y hermosa, pero la mercadotecnia y la moda nos hace vernos diferentes. Todos son hermosos, buenos, extraordinarios y fantásticos a su manera. Somos raros, somos diferentes, somos auténticos, somos únicos, no porque no nos parezcamos a los modelos, que la sociedad nos impone, significa que no tengamos belleza, pues la belleza se esconde dentro de la pureza del corazón de cada uno.

Los invito a vivir como hermanos, a ayudarnos como tales, a apoyarnos y a buscar el bien de todos, no nada más el de uno mismo. A dejar atrás las diferencias, los limites, las barreras, las fronteras, porque para amar no existen las fronteras y el hombre debe de amarse a si mismo tanto como a los que le rodean. Los invito a regalar sonrisas, palabras, enseñanzas, experiencias, cariño, amor y vida. Todos somos humanos, dejemos de usar etiquetas, él no es un gay, él tiene un nombre que le dieron al nacer y se le respeta. Ella no es una mala persona por hacer lo que le gusta, no le digan puta, zorra o de más, ella tiene también un nombre y también se le respeta. Ellos no son musulmanes, ni católicos, ni ateos, ni son cualquier otra religión, ellos tienen un nombre y por ese nombre llámenlos y respétenlos. Si tan solo pudiéramos concientizar al mundo, si tan solo podríamos crear una cultura que se sonríe, que se ayuda, que coexiste sin importar edad, raza, orientación o religión. Imagínense que sería de nuestro mundo y de la gente que vive en ella si todos veríamos por el bien del otro. Empieza por ti, por ustedes, por ellos, por todos.

Yo sí creo en este mundo, en que todos somos buenos, en que todos podemos cambiar, en que todos nos queremos ayudar, en que todos queremos vivir como nos gusta vivir y hacer lo que nos apasiona hacer. Creo en ti, creo en él, en ella, en ellos y en mí. Juntos podemos lograr cualquier cosa. ¡Empecemos hoy, pasa la voz, da el ejemplo y recuerda nunca dejar de sonreír!