The Eye of the Helix

Look Deep

The Helix Nebula as seen by the European Southern Observatory. (Click to embiggify.)

Well this is just stunning.  The Helix Nebula is a planetary nebula that lies about 700 light-years away from us. It’s what’s left over after a star like the Sun goes through its death throes and blows off much of its atmosphere to surrounding space. If you could float through the material to the central portion, you’d pass through shells of gas that were “exhaled” by the star. And, in the center would be the hot remnant of the old star, shining brightly in visible and ultraviolet light.

This image from the European Southern Observatory’s Very Large Telescope is full of detail in the surrounding clouds. For example, you can see little “blobs” of material that astronomers call “cometary knots”  — not because they’re comets (they’re not) but because they seem to have faint tails extending away from central blobs, pointing away from the star.

If you click on the image above you’ll get an enlarged version.  Look carefully at the central section of the nebula — you should be able to see galaxies in there!  The galaxies aren’t IN the nebula — they’re behind it, and the veil of gas is so thin that you can see much more distant objects right through it!

Go explore the eye of the  Helix — it’s gorgeous!  Want more information? Click here for the press release and links to zoom-in animations of the Helix.

OCO Lost

Lost Chance to Measure Atmospheric Carbon

The launch of the Orbiting Carbon Observatory (courtesy NASA).

The news today about the Orbiting Carbon Observatory (OCO) failed to reach orbit and crashed into the ocean near Antartica is just too ironic. The OCO (the acronym is also a play on the chemical formula for carbon dioxide, CO2) was built to measure places where carbon dioxide is being emitted and absorbed on and around our planet. Antarctica is one of the bellweather places on Earth that atmospheric scientists study as they chart the effects of global warming. OCO would have taken measurements 30,000 times per orbit, including the atmosphere over Antarctica. That’s the kind of fine detail that scientists need in order to understand and model the complexity of our atmosphere as it soaks up more and more carbon dioxide.

This is a huge loss.  How is it that a fairing — the part that protects the payload on the way up out of Earth’s gravity well — could fail?  Human error?  Part failure?  Did a computer command fail?  No matter how it was caused, the loss of this satellite affects not just the scientists involved, but students who had designed experiments using the satellite, and — really — all of us.

Antarctica, from a NASA animation.

Humans and our activities are the primary causes of excessive carbon dioxide levels in our atmosphere. That CO2 is part of the chain of events that are causing global warming. We need things like the OCO to help us understand the distribution, production, and absorption of CO2 if we are to make any definitive steps toward reducing the CO2 amounts we are pouring out each day from our automobiles, factories, power plants, and other polluting technologies. OCO is part of a larger effort to study and understand our planet — something we also do at other planets in order to understand their histories and environments. I hope that a replacement can be made for OCO — the knowledge it would have given us is information that we need.

Where Do Babies Come From?*

*Baby Dwarf Galaxies, That Is

In the 13.7-billion-year-long history of the universe, we know that galaxies had to come from somewhere, right?  It’s obvious that they were born, and we’re sitting inside one. And, since we can look out across great distances and see further back in time), you’d think we would be able to find galaxy “babies”. But, explaining the processes involved in galaxy building and observing them in action has been difficult. Part of the problem is that the galaxy formation section of our universe (if you want to think of it that way) is pretty far distant from us. That makes it tough to “see” unless you can look at galaxy birthplaces in different wavelengths of light.

The Galaxy Evolution Explorer (GALEX, a project run by NASA) looked out at the galaxy birthing fields  in the universe with ultraviolet eyes and turned up some pretty interesting action. Specifically, scientists using GALEX identified dwarf galaxies being born in clouds of pristine gas that could well have been left over from the creation of the universe itself.

Forming dwarf galaxies shine in ultraviolet light (objects in circles) as seen by the GALEX mission. The circled clumps are the dwarf galaxies found by the mission. Visible-light data (white) comes from the Digitized Sky Survey (STScI). The blue overlay comes from radio data provided by Arecibo Observatory. (Click to embiggen.)

They found unexpected new galaxies forming inside the Leo Ring, a huge cloud of hydrogen and helium that seems to hover around two huge galaxies in the constellation Leo. The whole complex lies around 35 million light-years away from us.

The cloud, which lies about 35 million light-years away from us, was first identified about 25 years ago in radio astronomy data. It’s not something you can see in visible light through an optical telescope.  Astronomers have tried exploring this ring, and all they found was gas. No stars of any kind could be seen at optical or radio wavelengths.  But, the GALEX satellite, with its ultraviolet light sensitivity found evidence of recent massive star formation in this region.

So, what’s the “smoking gun” signature of star formation in this ring? The ultraviolet signature of young stars is clearly seen coming from several clumps of gas within the Leo Ring.  Astronomer David Thilker of Johns Hopkins University thinks they’re dwarf galaxies.  “We speculate that these young stellar complexes are dwarf galaxies, although, as previously shown by radio astronomers, the gaseous clumps forming these galaxies lack dark matter,” he said. “Almost all other galaxies we know are dominated by dark matter, which acted as a seed for the collection of their luminous components — stars, gas and dust. What we see occurring in the Leo Ring is a new mode for the formation of dwarf galaxies in material remaining from the much earlier assembly of this galaxy group.”

Because they lack dark matter, these new galaxies astronomers are seeing in the Leo Ring resemble tidal dwarf galaxies (the kind that condense out of gas recycled from other galaxies), but  there’s an important difference. The gaseous material making up tidal dwarfs is rich with metals and elements that could only have been created inside stars.  The Leo Ring dwarfs are made of much more pristine material that doesn’t have ANY metals in it. Which means that no stars formed to “pollute” the gas making up the Leo Ring dwarfs.  Which gives astronomers a rare and new chance to study star formation in gases that are pristine leftovers from the creation of the universe.  There may have been a lot of these “pure” gas clouds early in universal history. As astronomers look farther out in space and further back in time with instruments like GALEX, they may find more of these baby galaxies being born.

You can get more information and images here about these baby galaxies and the GALEX mission.