Current Events in Astronomy

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Interesting current events about the study of the heavens.

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Will researchers finally be able to directly photograph a black hole?

What Will First Photos of Black Holes Look Like?

By Clara Moskowitz | SPACE.com

A giant black hole is thought to lurk at the center of the Milky Way, but it has never been directly seen. Now astronomers have predicted what the first pictures of this black hole will look like when taken with technology soon to be available.

In particular, researchers have found that pictures of a black hole ? or, more precisely, the boundaries around them ? will take a crescent form, rather than the blobby shape that is often predicted.

By modeling what these pictures will look like, scientists say they are preparing to interpret the photos that will become available from telescopes currently under construction.

"No one has been able to image a black hole," said University of California, Berkeley student Ayman Bin Kamruddin, who presented a poster on the research last week in Long Beach, Calif., at the 221st meeting of the American Astronomical Society. "So far it's been impossible because they're too small in the sky. Right now we're just getting some details about the structure, but we don't have an image yet." [Gallery: Black Holes of the Universe]

Black holes themselves are invisible, of course, as not even light can escape their gravitational clutches. However, the boundary of a black hole — the point of no return called the event horizon — should be visible from the radiation emitted by matter falling into the black hole.

"A black hole's immediate surroundings have a lot of really interesting physics going on, and they emit light," Kamruddin said. "Technically speaking, we aren't exactly seeing the black hole, but we are effectively resolving the event horizon."

A new project called the Event Horizon Telescope combines the resolving power of numerous antennas from a worldwide network of radio telescopes to sight objects that otherwise would be too tiny to make out.

"The Event Horizon Telescope is the first to resolve spatial scales comparable to the size of the event horizon of a black hole," said Kamruddin's collaborator, University of California, Berkeley astronomer Jason Dexter. "I don't think it's crazy to think we might get an image in the next five years."

The Event Horizon Telescope already has been gathering some preliminary measurements of the object called Sagittarius A* (pronounced "Sagittarius A-star") at the center of our Milky Way galaxy.

Kamruddin and Dexter have matched this data to various physical models and found that they best fit images that are crescent-shaped, rather than the blob shapes called "asymmetric Gaussians" that had been previously used in models.

The crescent shape emerges from the flat doughnut, called an accretion disk, formed by matter orbiting a black hole on its way to falling in. As gas spins around the black hole, one side of the disk comes toward view on Earth, and its light becomes brighter because of a process called Doppler beaming. The other side, representing receding gas, gets dimmer because of this effect.

In the center of the crescent is a dark circle called the black hole shadow, which represents the black hole itself — an incredibly dense object where space-time is extremely twisted.

"There's really extreme bending of light happening because of general relativity and the extremely strong gravitational field," Kamruddin said. Story Continues

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The journey to another star sytem begins with leaving our solar system.
Voyager 1 becomes first human-made object to leave solar system

By Elizabeth Landau

At the edge of the heliosphere, you wouldn't know by looking whether you left the cradle of humanity behind and floated out into interstellar space. You would just see unfathomably empty space, no matter which side of the invisible line you were on.

But scientists now have strong evidence that NASA's Voyager 1 probe has crossed this important border, making history as the first human-made object to leave the heliosphere, the magnetic boundary separating the solar system's sun, planets and solar wind from the rest of the galaxy.

"In leaving the heliosphere and setting sail on the cosmic seas between the stars, Voyager has joined other historic journeys of exploration: The first circumnavigation of the Earth, the first steps on the Moon," said Ed Stone, chief scientist on the Voyager mission. "That's the kind of event this is, as we leave behind our solar bubble."

A new study in the journal Science suggests that the probe entered the interstellar medium around August 25, 2012. You may have heard other reports that Voyager 1 has made the historic crossing before, but Thursday was the first time NASA announced it. Story Continues

[CasperParks]

The journey to another star sytem begins with leaving our solar system.
Voyager 1 becomes first human-made object to leave solar system

By Elizabeth Landau

At the edge of the heliosphere, you wouldn't know by looking whether you left the cradle of humanity behind and floated out into interstellar space. You would just see unfathomably empty space, no matter which side of the invisible line you were on.

But scientists now have strong evidence that NASA's Voyager 1 probe has crossed this important border, making history as the first human-made object to leave the heliosphere, the magnetic boundary separating the solar system's sun, planets and solar wind from the rest of the galaxy.

"In leaving the heliosphere and setting sail on the cosmic seas between the stars, Voyager has joined other historic journeys of exploration: The first circumnavigation of the Earth, the first steps on the Moon," said Ed Stone, chief scientist on the Voyager mission. "That's the kind of event this is, as we leave behind our solar bubble."

A new study in the journal Science suggests that the probe entered the interstellar medium around August 25, 2012. You may have heard other reports that Voyager 1 has made the historic crossing before, but Thursday was the first time NASA announced it. Story Continues

Good story. We don't hear enough from mainstream media on outer space.

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Plasma, the fourth state of matter, something I always associated with burning gas, not water!
Strange Super-Earth Planet Has 'Plasma' Water Atmosphere
by Nola Taylor Redd

A nearby alien planet six times the size of the Earth is covered with a water-rich atmosphere that includes a strange "plasma form" of water, scientists say.

Astronomers have determined that the atmosphere of super-Earth Gliese 1214 b is likely water-rich. However, this exoplanet is no Earth twin. The high temperature and density of the planet give it an atmosphere that differs dramatically from Earth.

"As the temperature and pressure are so high, water is not in a usual form (vapor, liquid, or solid), but in an ionic or plasma form at the bottom the atmosphere — namely the interior — of Gliese 1214 b," principle investigator Norio Narita of the National Astronomical Observatory of Japan told SPACE.com by email.

Using two instruments on the Subaru Telescope in Mauna Kea, Hawaii, scientists studied the scattering of light from the planet. Combining their results with previous observations led the astronomers to conclude that the atmosphere contained significant amounts of water.
Story Continues

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This galaxy appears as less than 1B years old. Just a baby!

Scientists confirm most distant galaxy ever

By Elizabeth Landau

Scientists say they've found a galaxy that's not just far, far, away -- it's the most distant from our own that's been discovered yet. And it's helping them gain insight about the universe as it existed a long time ago.

Astronomers say the galaxy, called z8_GND_5296, is the most remote one they can confirm with spectroscopy, a technique that looks for the chemical signatures of elements.

In this case, that element was hydrogen, the main fuel of stars. Researchers reported their findings in the journal Nature.

z8_GND_5296 -- no, that's not a typo, or a spam username -- is a window into the past. Because of its distance, it shows what things would have been like 700 million years after the Big Bang.

The universe is 13.8 billion years old, so 700 million years after the start is actually quite early by comparison.

Star formation

Besides breaking the distance record, astronomers find the new galaxy exciting because it appears to produce stars at an unusually high rate, said lead study author Steven Finkelstein, assistant professor of astronomy at the University of Texas at Austin.

Star-formation rate is measured by how much raw hydrogen the galaxy converts into new stars every year. The z8_GND_5296 galaxy converts hydrogen in the amount of 300 times the mass of our sun into new stars each year.

By contrast, the Milky Way only produces stars at one or two solar masses per year.

Scientists established through previous research that in the first billion years of the universe's history, typical rate of star formation went up, Finkelstein said. Galaxies formed more and more stars over time until about 10 billion years ago, when star formation rates began to decrease.
Story Continues

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The Cosmos News
Astronomers confirmed first Earth size planet in habitable zone: Kepler

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Got up at 6am today.
Picked up the newspaper and read there was a total lunar eclipse.... At 5am. D'oh!
Just missed it.

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Possibly mineral deposits? What do YOU think?

Weird Bright Spots on Dwarf Planet Ceres Still a Mystery in New Maps
by Elizabeth Howell

Strange bright spots on the surface of the Ceres continue to mystify scientists even as NASA's Dawn spacecraft is beaming the best maps yet of the dwarf planet in the asteroid belt.

The latest photos of Ceres from Dawn, which NASA released on Monday (April 13), were captured just before the spacecraft entered orbit around the dwarf planet in March. Dawn is now in the shadow of Ceres, forcing scientists to wait until later this month before catching their next day lit view of the surface.

While about 10 bright spots on Ceres have been detected in photos by the Hubble Space Telescope, the Dawn spacecraft has revealed that the two most prominent are in a crater about 57 miles wide (92 kilometers).
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About 10 weeks out and counting. The first close up/fly by shots of Pluto are on track for July 2015.

NASA's New Horizons probe is visiting Pluto — and just sent back its first color photos
by Joseph Stromberg

No spacecraft has ever visited Pluto. That's going to change on July 14, when NASA's New Horizons probe will fly within 6,200 miles of the dwarf planet after a nine-year journey.

"This is pure exploration," Alan Stern, the mission's principal investigator, said during a Tuesday press conference in which the probe's first color photos of Pluto and its moon Charon were released. "We’re going to turn points of light into a planet and a system of moons before your eyes."


...........Next month, New Horizons will start taking sharper ones. As Emily Lakdawalla of the Planetary Society puts it, every photo the probe takes will be the best photo ever taken of Pluto. They may show polar ice caps, mountains, and perhaps even volcanic activity.
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