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Archive for May, 2010

Swift and the Star-Eaters of the Cosmos: A New X-ray Census Reveals Secrets of Supermassive Black Holes Burning, Burning Brightly

May 27, 2010 4 comments
When galaxies merge, the supermassive black holes in their centers can light up as brilliantly bright galactic beacons.

When galaxies merge, the supermassive black holes in their centers can light up as brilliantly bright cosmic beacons.

I once was blind, but now I see. Astronomers who study the supermassive black holes beaming brightly at the centers of galaxies will be singing this line from “Amazing Grace” now.

Researchers using the Swift orbiting observatory demonstrated a way to detect virtually every supermassive black hole actively feeding on gas in nearby galaxies.

These galactic grazers are known in astrogeekspeak as “active galactic nuclei.” Active indeed! Imagine a mob of King Henry the 8ths tearing into railcars full of mutton, spewing gristle and gnawed leg bones in all directions. Active galactic nuclei — let’s just call them AGNs — are messy, voracious eaters, too, but they spew energy instead of table scraps. They can radiate more energy than all the billions of stars in the galaxy combined.

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Blogolicious Active Galactic Nuclei facts

  • Large galaxies contain supermassive black holes, with a million to a billion times the sun’s mass.
  • About 1% of the black holes are active galactic nuclei (AGNs), feeding on gas and emitting vast energy.
  • A survey by NASA’s Swift satellite finds that a quarter of AGNs are within merging galaxies or close pairs.
  • This is strong evidence for the theory that mergers trigger active galactic nuclei.

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But I digress: back to Swift.

A team of scientists observed the local universe with Swift’s Burst Alert Telescope (BAT), which sees in so-called hard X-rays. Those are the energetic rays that zip through your body during a medical scan. And what the scientists observed is that about a quarter of AGNs are in merging galaxies or close pairs of galaxies grabbing gravitationally at each other.

[Imagine loud “ah hah!” sound emanating collectively from the world’s galactic astronomers.]

Theorists have always said that most AGNs are probably powered by mergers. As the galaxies come together, it stirs up gas, which feeds the black holes. Now we have the “hard” (X-ray) evidence, and 6 years worth.

A sample of mergers-with-AGN found in the Swift hard X-ray census.

A sample of mergers-with-AGN found in the Swift census.

Once upon a time, many astronomers would have said that AGNs were fueled by stars being torn part near the supermassive black hole. This provides years worth of fuel. The shredded star spirals down into the hole to near-light speed, releasing gobs and gobs of energy.

This hypothesis is not off the royal banquet table just yet. Some AGNs may, in fact, be star gobblers. But the Swift result sure makes it look like many — maybe most? — AGNs trace to mergers.

With the Swift survey, astronomers have the cosmic equivalent of a well-done national census. Like good census data, it allows us to spot statistical trends and convince ourselves they are real. In this case, the trend is that many galaxies with AGNs are merging or closely interacting.

In contrast, observing galaxies at energies lower than hard X-rays can throw off a census. That’s because lower-energy light can be absorbed by all the gas and stuff tossed around by a merger. As a result, you may miss some of the AGNs.  Also, the AGNs bright optical emission can get lost in the overall glow of stars in the galaxy.

Look for the findings in the June 20 issue of The Astrophysical Journal Letters, if you care to graze on some real astrophysics.

ROLL THE CREDITS . . . Gogblog gratefully tips his supermassive hat to the study’s lead author, Michael Koss, a graduate student at the University of Maryland in College Park. He explained the science to Gogblog and reviewed the post for accuracy. Other members of the team include Richard Mushotzky and Sylvain Veilleux at the University of Maryland, College Park, and Lisa Winter at the Center for Astrophysics and Space Astronomy at the University of Colorado in Boulder.

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OH AND DID I MENTION? All opinions and opinionlike objects in this blog are mine alone and NOT those of NASA or Goddard Space Flight Center.


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Oh no! SDO is blowing my mind again! Blogolicious image of the day: May 20, 2010

May 20, 2010 8 comments
Area of details (below)

AREA OF DETAIL (BELOW)

I double-clicked this image a few minutes ago and heard a loud clanging sound in my head. It was the “SDO is blowing my mind again” alarm.

This image, captured by the Solar Dynamics Observatory on Tuesday this week, shows a dark filament of superhot gas, or plasma, suspended above the sun’s surface by magnetic fields. This filament is 22 times the width of Earth!

UPDATE: The filament is  estimated to be at least 60 Earth diameters long (about 500,000 miles).

The bright yellow-orange pockmarks around the filament are so-called active regions. Shafts of plasma emanate from the active regions, following (again) magnetic field lines emerging from the sun’s interior.

I could say more but I won’t. Just enlarge the image as much as you can and feast.

Gogblog tips his superheated plasma hat to Steele Hill, a media specialist with the SOHO, STEREO, and SDO missions. He sends gorgeous images and video of the sun out once per week to various institutions for public viewing, including the American Museum of Natural History and the Space Telescope Science Institute.

Click to make me bigger!

Click to make me bigger!

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OH AND DID I MENTION? All opinions and opinionlike objects in this blog are mine alone and NOT those of NASA or Goddard Space Flight Center.


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Highs and Lows from Ten Years of Terra, Flagship of the NASA Earth Observing System

May 18, 2010 2 comments
oil spill_304

The Terra satellite watches from orbit as an oil spill drifts toward the Louisiana Delta.

Change, as the old saying goes, is the only constant thing in the universe. Just over a decade ago, NASA launched a satellite called Terra to watch Earth’s surface and atmosphere. How is the planet changing and what are the consequences of change for life down here?

Last week, the Terra folks at Goddard held a private bash at our Visitor’s Center to celebrate Terra’s many accomplishments to date. Here are some of the various highs and lows of the mission that caught my eye:

HIGH: On December 18, 1999, Terra blasted off to a typical Earth-observing orbit 435 miles above the surface . . . It is 22 feet long and 11.5 feet wide, or about the size of a small school bus. Did I mention it weighed 5 tons (10,506 lbs) at launch at Vandenberg Air Force Base? . . In contrast, its high-tech lightweight solar panel weighed just 371 pounds because it was made up of solar cells fixed to a flexible blanket that unfurled in orbit. (Thanks to Eric Moyer, EOS Mission Director, for looking up that blogolicious science fact about Terra.)

The Terra spacecraft

The Terra spacecraft

LOW:  Millions of people grounded in Europe by drifting ash from Iceland’s (deep breath) Eyjafjallajokull Volcano. On May 13, Terra’s MODIS instrument observed the irritatingly unpronounceable volcano mixing it up with a local weather system.

HIGH:  Terra’s CERES instrument package measures how much solar energy Earth absorbs and how infrared radiation and heat is emitted back into space. Such sky-high measurements mean a lot for us puny groundlings, since Earth’s “energy balance” affects global climate.

LOW:  Terra told us that gases and particle that drag down air quality can be Asian imports transported long distances by the wind. The MOPITT instrument on Terra sniffs out carbon monoxide; the MODIS and MISR gizmo’s track tiny aerosol particles. Both carbon monoxide and aerosols influence air quality.

station fire_202HIGH:  Terra’s MISR instrument showed that large wildfires inject particles ands gases high into the atmosphere. This enables the smoke to drift long distances. For example, smoke from the high-flying plumes of the 2009 Station Fire drifted as far as Nevada, Utah, and Colorado. Carbon monoxide from the fire traveled at least as far as Louisiana.

mudslides_202LOW:  Terra’s ASTER instrument has proven a valuable tool for imaging mudslides, a notoriously murderous natural hazard sometimes unleashed by the combination of volcanic ash eruptions and heavy rainfall. In this image captured December 12, 2006, mudslides are black against a red background of plant-covered land. The populated towns Legazpi and Daraga are gray with white highlight from reflective surfaces.

Scientists and supporters of the Terra mission whoop it up at the Goddard Visitor Center.

Scientists and supporters of the Terra mission whoop it up at the Goddard Visitor Center.

Gogblog gratefully tips his blogolicious hat to Kathryn Hansen and Mike Carlowicz from NASA’s Earth Science News Team for their detailed account of Terra’s scientific accomplishments, from which much of this blog post was adapted.

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OH AND DID I MENTION? All opinions and opinionlike objects in this blog are mine alone and NOT those of NASA or Goddard Space Flight Center.


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Tweeps in Space! Twitter entwines a global community around NASA’s Solar Dynamics Observatory

not your mom's big old fat boring orange sun ball, is it?

not your mom's big old fat boring orange sun ball, is it?

So I went to this talk the other day about Twitter and spreading the gospel of the Solar Dynamics Observatory to the world. The talk came courtesy of a member of Goddard’s public outreach army, Aleya Van Doren. She works in what we NASA nerds call “formal education.” That just means she gets NASA science out into schools.

At the talk, Van Doren explained how she and other people here at Goddard used Twitter to build an enormous and active virtual community around the February 10 launch of our Solar Dynamics Observatory and the April 21 release of the first SDO images. Through the use of Twitter, they reached more than 5,000 students, 50 teachers, and thousands of people globally.

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Blogolicious Twitter Facts

  • Twitter surpassed 100 million registered users in April 2010
  • It could reach 1 billion by 2013.
  • 300,000 new users sign up daily.
  • Users send an average of 55 million tweets per day
  • 37 percent use their phone to tweet.

What are the sources for these Twitter facts? Well, this is one; this is another.

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SDO_firstlight_1_202One key take-home message for me: Twitter drew people into the event who otherwise wouldn’t have known or even cared about SDO. I know this because one of them tweeted Van Doren and said it.

The SDO first light images blew everyone away. They revealed in glorious detail and color the boiling, bubbling, burning, bodacious ball of inconceivably hot plasma that is our home star. Game-changing space observatories are what NASA excels at. Think of SDO as the Hubble Space Telescope for the sun.

It’s not hard to sell this stuff to the public. The images are beautiful. They reach you at a gut emotional level, trigger that throaty Keanu Reeves “whoa…..” you hear when people see the latest Hubble beauty shot.

That’s some powerful mojo, brothers and sisters. Like so many of my colleagues in the science communication racket, gogblog lustily desires to reach audiences more diverse than the “science fans” we serve so well.

I love that they love us, really I do. But it’s preaching to the choir. How do we get people who don’t go to church to jump in and sing with us?

Twitter can help. Here’s how.

The tagline for the launch event was #SDOisGO. Twitter aficionados of course know that #SDOisGO is a hashtag, which you include in a tweet to attach it to an ongoing discussion.

#SDOisGO was the focus of a national Tweetup for the SDO launch. 50 tweeps were invited to Goddard to watch the event remotely; alas Snowpocalypse 2010 smothered that plan.

But 15 invited “Twitter Correspondents” made it to Kennedy Space Center for the launch. Other groups of tweeters staged 30 events elsewhere in the country.

The twitter army deployed on February 11, launch day. On the ground at Kennedy, thumbs were twitching and tweeps were tweeting.

When SDO released its first light images April 21, 15 Twitter Correspondents articulated their thumbs to a frenzy of clicking at the NASA press conference in Washington, D.C. By then the #SDOisGO community was well established.

not ANOTHER spectacular new sun image! I can't take it!

not ANOTHER spectacular new sun image! I can't take it!

Some 5,000 students participated in classroom activities associated with the first light image release. In the day following the press conference, the size of the community swelled to 750,000 unique twitter users — enough to win “solar dynamics observatory” a place in the twittersphere as a trending topic.

No small feat for a science topic competing for attention with celebutantes and Justin Bieber.

Gogblog is jealous. So very very jealous.

The other big thing I took from the #SDOisGO experience is that twitter and other social media are not simply some alternative broadcast system to launch content at people. In fact, if you launch but never engage, people ignore you on twitter and won’t follow you.

People tweet because they like to meet people and have a communal experience. I guess it’s just what our little primate brains evolved to do.

So people like to meet other people, make new pals, and talk. And they are happy to talk about SDO, or other interesting things. As long as you engage them on a human level.

Me gogblog, you friend?

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OH AND DID I MENTION? All opinions and opinionlike objects in this blog are mine alone and NOT those of NASA or Goddard Space Flight Center.


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