Contributor Posts

NASA Astronomy Picture of the Day:

In the upper left corner, surrounded by blue arms and dotted with red nebulas, is spiral galaxy M81. In the lower right corner, marked by a light central line and surrounded by red glowing gas, is irregular galaxy M82. This stunning vista shows these two mammoth galaxies locked in gravitational combat, as they have been for the past billion years. The gravity from each galaxy dramatically affects the other during each hundred-million-year pass. Last go-round, M82's gravity likely raised density waves rippling around M81, resulting in the richness of M81's spiral arms. But M81 left M82 with violent star forming regions and colliding gas clouds so energetic the galaxy glows in X-rays. This big battle is seen from Earth through the faint glow of an Integrated Flux Nebula, a little studied complex of diffuse gas and dust clouds in our Milky Way Galaxy. In a few billion years, only one galaxy will remain.

Photo by Collaborative Astrophotography Team (CAT)

NASA Astronomy Picture of the Day:

If one black hole looks strange, what about two? Light rays from accretion disks around a pair of orbiting supermassive black holes make their way through the warped space-time produced by extreme gravity in this detailed computer visualization. The simulated accretion disks have been given different false color schemes, red for the disk surrounding a 200-million-solar-mass black hole, and blue for the disk surrounding a 100-million-solar-mass black hole. For these masses, though, both accretion disks would actually emit most of their light in the ultraviolet. The video allows us to see both sides of each black hole at the same time. Red and blue light originating from both black holes can be seen in the innermost ring of light, called the photon sphere, near their event horizons. In the past decade, gravitational waves from black hole collisions have actually been detected, although the coalescence of supermassive black holes remains undiscovered. Hole New Worlds: It's Black Hole Week at NASA!

NASA Astronomy Picture of the Day:

What’s causing those lines? Objects in the sky sometimes appear reflected as lines across water — but why? If the water’s surface is smooth, then reflected objects would appear similarly -- as spots. But if the water is choppy, then there are many places where light from the object can reflect off the water and still come to you -- and so together form, typically, a line. The same effect is frequently seen for the Sun just before sunset and just after sunrise. Pictured about 10 days ago in Ibiza, Spain, images of the rising Moon, Venus (top), and Saturn (right, faint) were captured both directly and in line-reflected forms from the Mediterranean Sea. The other bright object on the right with a water-reflected line is a beacon on a rock to warn passing boats. Explore Your Universe: Random APOD Generator

Photo by Jose Antonio Hervas

Marcus Aurelius Antonius (121 – 180) was Roman emperor from 161 to 180 AD and a Stoic philosopher. He was the last of the rulers known as the Five Good Emperors (a term coined some 13 centuries later by Niccolò Machiavelli), and the last emperor of the Pax Romana, an age of relative peace, calmness and stability for the Roman Empire lasting from 27 BC to 180 AD. He served as Roman consul in 140, 145, and 161. Meditations, the writings of "the philosopher" – as contemporary biographers called Marcus – are a significant source of the modern understanding of ancient Stoic philosophy. These writings have been praised by fellow writers, philosophers, monarchs, and politicians centuries after his death.

NASA Astronomy Picture of the Day:

How fast can a black hole spin? If any object made of regular matter spins too fast -- it breaks apart. But a black hole might not be able to break apart -- and its maximum spin rate is really unknown. Theorists usually model rapidly rotating black holes with the Kerr solution to Einstein's General Theory of Relativity, which predicts several amazing and unusual things. Perhaps its most easily testable prediction, though, is that matter entering a maximally rotating black hole should be last seen orbiting at near the speed of light, as seen from far away. This prediction was tested by NASA's NuSTAR and ESA's XMM satellites by observing the supermassive black hole at the center of spiral galaxy NGC 1365. The near light-speed limit was confirmed by measuring the heating and spectral line broadening of nuclear emissions at the inner edge of the surrounding accretion disk. Pictured here is an artist's illustration depicting an accretion disk of normal matter swirling around a black hole, with a jet emanating from the top. Since matter randomly falling into the black hole should not spin up a black hole this much, the NuSTAR and XMM measurements also validate the existence of the surrounding accretion disk. Hole New Worlds: It's Black Hole Week at NASA!

NASA Astronomy Picture of the Day:

Like Earth's moon, Saturn's largest moon Titan is locked in synchronous rotation with its planet. This mosaic of images recorded by the Cassini spacecraft in May of 2012 shows its anti-Saturn side, the side always facing away from the ringed gas giant. The only moon in the solar system with a dense atmosphere, Titan is the only solar system world besides Earth known to have standing bodies of liquid on its surface and an earthlike cycle of liquid rain and evaporation. Its high altitude layer of atmospheric haze is evident in the Cassini view of the 5,000 kilometer diameter moon over Saturn's rings and cloud tops. Near center is the dark dune-filled region known as Shangri-La. The Cassini-delivered Huygens probe rests below and left of center, after the most distant landing for a spacecraft from Earth.

NASA Astronomy Picture of the Day:

The most massive young star cluster in the Small Magellanic Cloud is NGC 346, embedded in our small satellite galaxy's largest star forming region some 210,000 light-years distant. Of course the massive stars of NGC 346 are short lived, but very energetic. Their winds and radiation sculpt the edges of the region's dusty molecular cloud triggering star-formation within. The star forming region also appears to contain a large population of infant stars. A mere 3 to 5 million years old and not yet burning hydrogen in their cores, the infant stars are strewn about the embedded star cluster. This spectacular infrared view of NGC 346 is from the James Webb Space Telescope's NIRcam. Emission from atomic hydrogen ionized by the massive stars' energetic radiation as well as molecular hydrogen and dust in the star-forming molecular cloud is detailed in pink and orange hues. Webb's sharp image of the young star-forming region spans 240 light-years at the distance of the Small Magellanic Cloud.

To the living, I am gone.
To the sorrowful, I will never return.
To the angry, I was cheated 
But to the happy, I am at peace
And to the faithful, I have never left...

...For if you always think of me, I will never be gone. Read the full poem

NASA Astronomy Picture of the Day:

The first to orbit inner planet Mercury, the MESSENGER spacecraft came to rest on this region of Mercury's surface on April 30, 2015. Constructed from MESSENGER image and laser altimeter data, the projected scene looks north over the northeastern rim of the broad, lava filled Shakespeare basin. The large, 48 kilometer (30 mile) wide crater Janacek is near the upper left edge. Terrain height is color coded with red regions about 3 kilometers above blue ones. MESSENGER'S final orbit was predicted to end near the center, with the spacecraft impacting the surface at nearly 4 kilometers per second (over 8,700 miles per hour) and creating a new crater about 16 meters (52 feet) in diameter. The impact on the far side of Mercury was not observed by telescopes, but confirmed when no signal was detected from the spacecraft given time to emerge from behind the planet. Launched in 2004, the MErcury Surface, Space ENvironment, GEochemisty and Ranging spacecraft completed over 4,000 orbits after reaching the Solar System's innermost planet in 2011.

             Spring Night

The park is filled with night and fog,
The veils are drawn about the world,
The drowsy lights along the paths
Are dim and pearled.

Gold and gleaming the empty streets,
Gold and gleaming the misty lake,
The mirrored lights light sunken swords,
Glimmer and shake.

Oh, is it not enough to be
Here with this beauty over me?
My throat should ache with praise, and I
Should kneel in joy beneath the sky.
Oh, beauty, are you not enough?

Why am I crying after love
With youth, a singing voice and eyes
To take earth’s wonder with surprise?
Why have I put off my pride,
Why am I unsatisfied,

I for whom the pensive night
Binds her cloudy hair with light,
I for whom all beauty burns
Like incense in a million urns?
Oh, beauty, are you not enough?
Why am I crying after love?

Sara Teasdale (1884 – 1933) was an American lyric poet. She was born Sarah Trevor Teasdale in St. Louis, Missouri, and used the name Sara Teasdale Filsinger after her marriage in 1914. She is the author of many poetry collections and was awarded the Pulitzer Prize for her "Love Songs"  Read more  

This poem is in the public domain.

NASA Astronomy Picture of the Day:

Sometimes, the sky itself seems to smile. A few days ago, visible over much of the world, an unusual superposition of our Moon with the planets Venus and Saturn created just such an iconic facial expression. Specifically, a crescent Moon appeared to make a happy face on the night sky when paired with seemingly nearby planets. Pictured is the scene as it appeared over Zacatecas, México, with distinctive Bufa Hill in the foreground. On the far right and farthest in the distance is the planet Saturn. Significantly closer and visible to Saturn's upper left is Venus, the brightest planet on the sky. Just above the central horizon is Earth's Moon in a waning crescent phase. To create this gigantic icon, the crescent moon phase must be smiling in the correct direction. Dial-A-Moon: Find the Moon phase on your birthday this year

Photo by Daniel Korona

"The problem with climate change isn’t just the temperature – it’s also how fast the climate is changing today.
Historically, Earth’s climate changes have generally happened over thousands to millions of years. Today, global temperatures are increasing by about 0.36 degrees Fahrenheit (0.2 degrees Celsius) per decade". More at The Conversation ➜