Picture Of The Day 2 - November 17, 2018

Picture of the day - December 6, 2018

Another picture of the fifth planet of the Insight B system.

Evaporating Planets

Picture of the Day - October 27, 2018

These three planets (not comets) close to a white giant star losing their atmospheres. The giant star has expanded so fast that all of the inner planets are superheated to nearly 2,000 F.

Pictures of the day - November 24, 2018

Venus-like world with two moons in orbit. I had to use the editor in Space Engine to get a true Venus-Like appearance for this world.

I am not a fan of how some of the planets appear in the game, luckily an editor is provided in order to make some of these worlds appear more realistic.

Space Engine System ID: RS 5581-42-1-2-487 2

High Resolution Pictures

Venus Analog

Two moons

Stormy planet

Closeup

Blue Titan

Picture of the day - October 12, 2018.

Blue-tinted Titan-Like world with liquid methane oceans and an extensive ring system.

Picture of the Day - February 7, 2019 - (Late Post)

The limb of a gas giant orbiting Wolf 359.

TRAPPIST - 1 by Guillem H. Pongiluppi

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)

Pictures of the day 2 - December 4, 2018

Insight B System - Sixth Planet (Insight B-VI)

Insight B-VI is the outer-most planet orbiting Insight B. The planet is a Jupiter-Sized gas giant with a mass of 1.42 Jupiter Masses, and a radius of 74,962 kilometers. A thick carbon-rich ring system surround the planet.

Insight B-VI orbits its sun at an average distance of 1.74 AU, completing an orbit once every 2.79 Earth Years. A day on the planet lasts only 8 hours and 7 minutes. It is a frigid giant, the atmosphere of which averages -258 F. Monstrous storms rage in the planet’s atmosphere, powered by internally released heat.

The planet is the only world in the system to by surrounded by a major lunar system. Three massive moons larger than Mars orbit the planet, along with 3 smaller rounded satellites, and 74 asteroid-like moons.

High Resolution Pictures

Insight B-VI

South Pole

Giant Storm

Inner-most Major Moon.

Approaching Eclipse

Lunar Rings

Pictures of the Day - October 21, 2018

Normally, giant planets are the ones with rings, but in some situations a moon of a gas giant can have its own rings. Here we come across such a satellite.

I know there’s a lot of tension after Tumblr’s new policy annouced for December 17th, but reblog this if you aren’t leaving Tumblr so that other blogs can know they aren’t going to be completely alone!