M104: The Sombrero Galaxy.

on the first day of class my astronomy professor asked us why the night sky was dark. if our universe is infinite, how can there be spaces between the stars? he didn’t answer the question until the last day– because our universe is relatively young, and is still growing. it is finite. not enough stars or galaxies have been formed to fill up the entire night sky.

but what that means to me is that somewhere, in an older universe, the night sky looks like a tapestry of diamonds. somewhere darkness is pale white and glittering. imagine being so surrounded. i haven’t gotten that image out of my head ever since– you could never navigate under such a sky but god it sounds lovely

IC 1805, Center of the Heart

The planet Saturn, brought to you by the Hubble Space Telescope.

some of my favourite absolutely SICK facts about the trappist-1 exoplanets: - theyre all very close to one another and to their star, so the length of a year on them varies from 1 to 20 DAYS - since they’re so close, the star appears a lot bigger than our sun from earth, and from one planet you could easily see the rest, some would even appear bigger than the moon from earth. you could literally see the surface of another planet with the naked eye!!! - they’re probably tidally locked to their star like our moon is locked to earth, meaning only one side of a planet ever faces the star, and on the other side it’s always night. the sun never sets or rises on any of the planets - the star is red, so the sunlight is red/orange, meaning if, for example, plants were to grow there, they could be black and that’s just what we know now, imagine how much cool stuff we have yet to discover about the trappist-1 system

A Blue Bridge of Stars between Cluster Galaxies designated SDSS J1531+3414

js

The Boomerang Nebula (Bow-tie Nebula)

The Boomerang Nebula is about 5000 light years away  from the Earth, situated in the constellation Centaurus and is the coldest place known in the entire universe at a temperature of  1K. According to the astronomers, the nebula houses a central dying star which has been losing one-thousandth of  a solar mass of material from the last 1500 years. The bow-tie shape of the nebula is said to have formed due to very fierce winds (blowing at about 500,000 kmph) blowing the ultra cold gas away from the dying star.

Image credit: Hubble/NASA/ESA

Light Echoes from V838 Mon

For reasons unknown, star V838 Mon’s outer surface suddenly greatly expanded with the result that it became the brightest star in the entire Milky Way Galaxy in January 2002. Then, just as suddenly, it faded. A stellar flash like this has never been seen before.

It’s true that supernovae and novae expel matter out into space. But while the V838 Mon flash appears to expel material into space, what is seen here is actually an outwardly moving light echo of the bright flash. In a light echo, light from the flash is reflected by successively more distant rings in the ambient interstellar dust that already surrounded the star.

V838 Mon lies about 20,000 light years away toward the constellation of Monoceros the unicorn. In this Hubble Space Telescope image from February 2004, the light echo is about six light years in diameter.

Image Credit: NASA, APOD, ESA, H. E. Bond (STScI)

Steve Gildea Planetary Suite, circa 1990

Comas and Tails of Comets The generally unexpected and sometimes spectacular appearance of comets have triggered the interest of many people throughout history. A bright comet can easily be seen with the naked eye. Comets are usually not discovered until after a coma or tail has formed. Depending on the apparent size of the coma or tail, a comet can be very bright. Some comets have a tail extending more than 45˚ on the sky. The earliest records of comet observations date to ~6000BCE in China. The smaller nucleus (rocky body) of a comet, often only a few kilometres in diameter, is usually hidden from view by the large coma, a cloud of gas and dust roughly 10 to the power of 4-10 to the power of 5 km in diameter and not seen with the naked eye, a large hydrogen coma, between 1 and 10 million km in extent, which surrounds the nucleus and visible gas/dust coma. Two tails are often visible, both in the antisolar direction: a curved yellowish dust tail and a straight ion tail, usually of a blue colour. Comets are usually inert at large heliocentric distances and only develop a coma and tails when they get closer to the sun. When the sublimating gas evolves off the surface of a comet’s nucleus, dust is dragged along. The gas and dust form a comet’s coma and hide the nucleus from view. Most comets are discovered after the coma has formed when they are bright enough to be seen with relatively small telescopes. ~ JM Image Credit More Info: Comets, NASA Coma

The full rotation of the Moon as seen by NASA’s Lunar Reconnaissance Orbiter