What Is A Wormhole?

Picture of the Day - February 2, 2019 - (Very Late Post)

The core of a galaxy.

Blue Ring

Picture of the day - November 3, 2018

A cold ice-world with a thick nitrogen atmosphere backlit against a blue B-type sun. The star is so bright that all objects, even some asteroids reflect enough light to be visible orbiting close to the star. The comet-looking object is not a comet, but a planet getting its atmosphere burnt away by the sun.

R136a1 System

A visit to a more familiar system in the Large Magellanic Cloud Galaxy. The program depicts a large gas orbiting the star at a distance of 738.59 AU along with several large moons.

R136a1 is believed to be the most massive known star with a mass 315 times that of our sun. The star shines with a luminosity of 8.7 million suns. The gas giant even at its extreme orbital distance of 738.59 AU, still receives more solar radiation than Earth.

High Resolution Images

Bright Blue Sun

Inner Dwarf Planet from a moon

Outer moon.

Approaching eclipse

Double moons

Picture of the day 2 - January 6, 2019

Titan-Like World.

Moon Halo

Credit: Mikhail Reva

Colorful Desert World

Picture of the day 2 - November 8, 2019

A rather vibrant desert-type planet with active weather.

O’Sirus System - Post 2 (Weird Life)

The System’s 6th planet, and first world I’ve come across in my journey that has life on the surface. This is one odd life-supporting world. It is a small world, roughly the size of Mars, but only half of Mars’ mass, with a low average density. The atmosphere is 99.8% carbon dioxide and 0.2% oxygen, with a thickness only 4% that of Earth’s atmosphere. The surface has an average temperature of 181 K or -133 °F.  And it has one large moon in orbit.

Unfortunately Space Engine only shows life as coloring on the planet’s surface; therefore, I have no idea what form or appearance it has. Based off of the temperatures and atmospheric composition, this the life likely has has a low metabolic rate that uses a liquid other than just water to metabolize, possibly an Eutectic Water-Ammonia solution. Carbon-based if feasible, but involves significantly different chemistry than we are familiar with. The purple coloring likely an adaptation to utilize the low sunlight levels and probably uses primarily red or near infrared light for photosynthesis.

High Resolution Pics

Picture 1 - Planet and Moon

Picture 2 -

Picture 3 - The Equator

Picture 4 - Northern Ice Cap

Picture 5 - Planet, Moon, Sun, Inner Planets and Andromeda

Picture 6 - The Surface

Picture 7 - Moon and Nebula Rising

Picture of the Day - January 30, 2019 - (Very late post)

Violet-colored planet with its two moons.

Galaxies: Types and morphology

A galaxy is a gravitationally bound system of stars, stellar remnants, interstellar gas, dust, and dark matter. Galaxies range in size from dwarfs with just a few hundred million (108) stars to giants with one hundred trillion (1014) stars, each orbiting its galaxy’s center of mass.

Galaxies come in three main types: ellipticals, spirals, and irregulars. A slightly more extensive description of galaxy types based on their appearance is given by the Hubble sequence. 

Since the Hubble sequence is entirely based upon visual morphological type (shape), it may miss certain important characteristics of galaxies such as star formation rate in starburst galaxies and activity in the cores of active galaxies.

Ellipticals

The Hubble classification system rates elliptical galaxies on the basis of their ellipticity, ranging from E0, being nearly spherical, up to E7, which is highly elongated. These galaxies have an ellipsoidal profile, giving them an elliptical appearance regardless of the viewing angle. Their appearance shows little structure and they typically have relatively little interstellar matter. Consequently, these galaxies also have a low portion of open clusters and a reduced rate of new star formation. Instead they are dominated by generally older, more evolved stars that are orbiting the common center of gravity in random directions.

Spirals

Spiral galaxies resemble spiraling pinwheels. Though the stars and other visible material contained in such a galaxy lie mostly on a plane, the majority of mass in spiral galaxies exists in a roughly spherical halo of dark matter that extends beyond the visible component, as demonstrated by the universal rotation curve concept.

Spiral galaxies consist of a rotating disk of stars and interstellar medium, along with a central bulge of generally older stars. Extending outward from the bulge are relatively bright arms. In the Hubble classification scheme, spiral galaxies are listed as type S, followed by a letter (a, b, or c) that indicates the degree of tightness of the spiral arms and the size of the central bulge.

Barred spiral galaxy

A majority of spiral galaxies, including our own Milky Way galaxy, have a linear, bar-shaped band of stars that extends outward to either side of the core, then merges into the spiral arm structure. In the Hubble classification scheme, these are designated by an SB, followed by a lower-case letter (a, b or c) that indicates the form of the spiral arms (in the same manner as the categorization of normal spiral galaxies). 

Ring galaxy

A ring galaxy is a galaxy with a circle-like appearance. Hoag’s Object, discovered by Art Hoag in 1950, is an example of a ring galaxy. The ring contains many massive, relatively young blue stars, which are extremely bright. The central region contains relatively little luminous matter. Some astronomers believe that ring galaxies are formed when a smaller galaxy passes through the center of a larger galaxy. Because most of a galaxy consists of empty space, this “collision” rarely results in any actual collisions between stars.

Lenticular galaxy

A lenticular galaxy (denoted S0) is a type of galaxy intermediate between an elliptical (denoted E) and a spiral galaxy in galaxy morphological classification schemes. They contain large-scale discs but they do not have large-scale spiral arms. Lenticular galaxies are disc galaxies that have used up or lost most of their interstellar matter and therefore have very little ongoing star formation. They may, however, retain significant dust in their disks.

Irregular galaxy

An irregular galaxy is a galaxy that does not have a distinct regular shape, unlike a spiral or an elliptical galaxy. Irregular galaxies do not fall into any of the regular classes of the Hubble sequence, and they are often chaotic in appearance, with neither a nuclear bulge nor any trace of spiral arm structure.

Dwarf galaxy

Despite the prominence of large elliptical and spiral galaxies, most galaxies in the Universe are dwarf galaxies. These galaxies are relatively small when compared with other galactic formations, being about one hundredth the size of the Milky Way, containing only a few billion stars. Ultra-compact dwarf galaxies have recently been discovered that are only 100 parsecs across.

Interacting

Interactions between galaxies are relatively frequent, and they can play an important role in galactic evolution. Near misses between galaxies result in warping distortions due to tidal interactions, and may cause some exchange of gas and dust. Collisions occur when two galaxies pass directly through each other and have sufficient relative momentum not to merge.

Starburst

Stars are created within galaxies from a reserve of cold gas that forms into giant molecular clouds. Some galaxies have been observed to form stars at an exceptional rate, which is known as a starburst. If they continue to do so, then they would consume their reserve of gas in a time span less than the lifespan of the galaxy. Hence starburst activity usually lasts for only about ten million years, a relatively brief period in the history of a galaxy.

Active galaxy

A portion of the observable galaxies are classified as active galaxies if the galaxy contains an active galactic nucleus (AGN). A significant portion of the total energy output from the galaxy is emitted by the active galactic nucleus, instead of the stars, dust and interstellar medium of the galaxy.

The standard model for an active galactic nucleus is based upon an accretion disc that forms around a supermassive black hole (SMBH) at the core region of the galaxy. The radiation from an active galactic nucleus results from the gravitational energy of matter as it falls toward the black hole from the disc. In about 10% of these galaxies, a diametrically opposed pair of energetic jets ejects particles from the galaxy core at velocities close to the speed of light. The mechanism for producing these jets is not well understood.

The main known types are: Seyfert galaxies, quasars, Blazars, LINERS and Radio galaxy.

source

images: NASA/ESA, Hubble (via wikipedia)