Start Exploring The Universe Today!

Pictures of the Day

50 Miles on Pluto

A 50 mile (80 kilometer) trip across Pluto would cover the distance indicated by the scale bar in this startling image. The close-up of the icy world's rugged equatorial terrain was captured when the New Horizons spacecraft was about 47,800 miles (77,000 kilometers) from the surface, 1.5 hours before its closest approach. Rising to an estimated 11,000 feet (3,500 meters) the mountains are likely composed of water ice. Suggesting surprising geological activity, they are also likely young with an estimated age of 100 million years or so based on the apparent absence of craters. The region pictured is near the base of Pluto's broad, bright, heart-shaped feature.

2015-07-16

Moon over Byzantium

Hiding near the Sun, a slender crescent Moon is a difficult but rewarding sight. Look to the right (scroll right) and you can spot one in this twilight panorama across the Bosporus Strait and along the skyline of the historic city of Istanbul. Recorded on March 8, the Moon is a mere 22 hours young. A thin, curved edge of the Moon's illuminated surface is just visible poised in the western sky at sunset above the walls of Topkapi Palace. The palace was built in the reign of Ottoman Sultan Mehmed II, the 15th century conquerer of the city that was then Constantinople, capital of the Byzantine Empire. The well-lit domed building immediately to the left of the palace is Ayasofya (Hagia Sophia), a famous example of Byzantine architecture, now a museum. Still farther to the left is the Sultan Ahmed Mosque

2008-03-15

Stars of a Summer's Triangle

Rising at the start of a northern summer's night, these three bright stars form the familiar asterism known as the Summer Triangle. Altair, Deneb, and Vega are the alpha stars of their respective constellations, Aquila, Cygnus, and Lyra, nestled near the Milky Way. Close in apparent brightness the three do look similar in these telescopic portraits, but all have their own stellar stories. Their similar appearance hides the fact that the Summer Triangle stars actually span a large range in intrinsic luminosity and distance. A main sequence dwarf star, Altair is some 10 times brighter than the Sun and 17 light-years away, while Vega, also a hydrogen-fusing dwarf, is around 30 times brighter than the Sun and lies 25 light-years away. Supergiant Deneb, at about 54,000 times the solar luminosity, lies some 1,400 light-years distant. Of course, with a whitish blue hue, the stars of the Summer Triangle are all hotter than the Sun.

2015-06-27

The Annotated Galactic Center

The sky toward the center of our Galaxy is filled with a wide variety of celestial wonders. Many are easily visible with binoculars. Constellations near the galactic center include Sagittarius, Libra, Scorpius, Scutum, and Ophiuchus. Nebulae include Messier Objects M8, M16, M17, M20 and the Pipe Nebula. Open star clusters include M6, M7, M18, M21, M23, M24, M25. Globular star clusters include M9, M22, M28, M54, M69, M70. And don't forget Baade's Window. Click on the photo to get the un-annotated version.

1999-09-11

Saturn: Lord of the Rings

Born in 1564, Galileo used a telescope to explore the Solar System. In 1610, he became the first to be amazed by Saturn's rings, After nearly 400 years, Saturn's magnificent rings still offer one of the most stunning astronomical sights. Uniquely bright compared to the rings of the other gas giants, Saturn's ring system is around 250,000 kilometers wide but in places only a few tens of meters thick. Modern astronomers believe the rings are perhaps only a hundred million years young. Accumulating dust and dynamically interacting with Saturn's moons, the rings may eventually darken and sag toward the gas giant, losing their lustre over the next few hundred million years. Since Galileo, astronomers have subjected the entrancing rings to intense scrutiny to unlock their secrets. On December 31, 2003, Saturn made its closest approach to Earth for the next 29 years, a mere 1,200,000,000 kilometers. It will remain a tantalizing target for earthbound telescopes in the coming months.

2004-01-17

3D Bennu

Put on your red/blue glasses and float next to asteroid 101955 Bennu. Shaped like a spinning toy top with boulders littering its rough surface, the tiny Solar System world is about one Empire State Building (less than 500 meters) across. Frames used to construct this 3D anaglyph were taken by PolyCam on the OSIRIS_REx spacecraft on December 3, 2018 from a distance of about 80 kilometers. With a sample from the asteroid's rocky surface on board, OSIRIS_REx departed Bennu's vicinity in May of 2021 and is now enroute to planet Earth. The robotic spacecraft is scheduled to return the sample to Earth this September.

2023-03-11

IC 5146: The Cocoon Nebula

Inside the Cocoon Nebula is a newly developing cluster of stars. Cataloged as IC 5146, the beautiful nebula is nearly 15 light-years wide. Soaring high in northern summer night skies, it's located some 4,000 light years away toward the constellation Cygnus the Swan. Like other star forming regions, it stands out in red, glowing, hydrogen gas excited by young, hot stars, and dust-reflected starlight at the edge of an otherwise invisible molecular cloud. In fact, the bright star found near the center of this nebula is likely only a few hundred thousand years old, powering the nebular glow as it clears out a cavity in the molecular cloud's star forming dust and gas. A 29 hour long integration with a small telescope from Ayr, Ontario, Canada resulted in this exceptionally deep color view tracing tantalizing features within and surrounding the dusty stellar nursery.

2022-08-27

Colorful Clouds of Orion

Revisiting one of the most famous nebulae in planet Earth's night sky, astrophotographer Robert Gendler has constructed this stunning, color-enhanced mosaic of the region surrounding the Great Nebula in Orion. As seen here, the clouds of Orion are dominated by the reddish emission nebula M42 near the bottom of the image, with blue reflection nebulae, including NGC 1977, near the top. Strewn with dust lanes and dark nebulae, the striking cosmic apparitions surrounding Orion's stellar nurseries are about 1,500 light-years away and are themselves several light-years across. Located at the edge of a giant molecular cloud complex spanning hundreds of light-years, these nebulae represent only a small, but very visible(!), fraction of this region's wealth of interstellar material. Within these colorful clouds of Orion, astronomers have also identified what appear to be numerous infant solar systems.

2002-12-20

NGC 4676: When Mice Collide

These two mighty galaxies are pulling each other apart. Known as "The Mice" because they have such long tails, each spiral galaxy has likely already passed through the other. They will probably collide again and again until they coalesce. The long tails are created by the relative difference between gravitational pulls on the near and far parts of each galaxy. Because the distances are so large, the cosmic interaction takes place in slow motion -- over hundreds of millions of years. NGC 4676 lies about 300 million light-years away toward the constellation of Bernice's Hair (Coma Berenices) and are likely members of the Coma Cluster of Galaxies. The above picture was taken with the Hubble Space Telescope's Advanced Camera for Surveys which is more sensitive and images a larger field than previous Hubble cameras. The camera is scheduled to be serviced during the coming flight of Space Shuttle.

2009-04-26

The Rotten Egg Planetary Nebula

Not all evolving stars eject gas clouds that look like people. OH231.8+4.2 was a star much like our Sun that ran out of nuclear fuel to fuse in its core. It has therefore entered the planetary nebula phase, where it throws off its outer atmosphere into space leaving a core that will become a white dwarf star. Every Sun-like star creates a different planetary nebula though, and OH231.8+4.2's looks eerily like a person! Spectacular jets of streaming gas can be seen in this recently released photograph by the Hubble Space Telescope. The gas cloud has been dubbed the Rotten Egg Planetary Nebula because it contains unusually high amounts of sulfur, an element that, when combined with other elements, can smell like a rotten egg. This young planetary nebula will likely change its appearance over the next few thousand years and eventually disperse.

1999-11-01

The Medusa Nebula

Braided, serpentine filaments of glowing gas suggest this nebula's popular name, The Medusa Nebula. Also known as Abell 21, this Medusa is an old planetary nebula some 1,500 light-years away along the southern border of the constellation Gemini. Like its mythological namesake, the nebula is associated with a dramatic transformation. The planetary nebula phase represents a final stage in the evolution of low mass stars like the sun, as they transform themselves from red giants to hot white dwarf stars and in the process shrug off their outer layers. Ultraviolet radiation from the hot star powers the nebular glow. An unrelated, bright, foreground star is near center in this close-up, telescopic view, while the Medusa's transforming central star is actually the dimmer star below center and toward the right-hand part of the frame. The Medusa Nebula is estimated to be over 4 light-years across.

2015-06-12

The International Space Station Expands Again

The developing International Space Station (ISS) has changed its appearance yet again. Last month the Space Shuttle Atlantis visited the ISS and installed the third of eleven pieces that will compose the Integrated Truss Structure. The new S-1 Truss is visible on the right, below the extended solar panels across the top. The world's foremost space outpost can be seen developing over the past few years by comparing the above image to past images. Also visible above are many different types of modules, a robotic arm, several wing-like solar panels, and a supply ship. Construction began on the ISS in 1998 and the core structure should be in place before 2005. Yesterday, the ISS celebrated its second anniversary of continuous human habitation.

2002-11-03