New Planetary Neighborhoods

New Worlds: Not SF Anymore!

An artist’s concept of stars with planets orbiting them. This one shows multiple-transiting planet systems, which are stars with more than one planet. The planets eclipse or transit their host star from the vantage point of the observer. This angle is called edge-on. Image Credit: NASA

I know the news about the new planets has really grabbed people this past week. There’s something about distant worlds that excites the science fiction-lover inside each of us.  And, Kepler has found another 715 new worlds among the myriad of observations it has made.

What kind of worlds are they?  The statistics are fascinating. Around 95 percent of them are smaller than our planet Neptune. That’s a big step forward. It means that we’re able to detect smaller worlds now, although it does take a bit longer to confirm them since they’re — well, small. Which makes them harder to spot in the followup observations. Many of them are in multiple-world systems, similar to ours, which has planets, moons, and outer worlds not even discovered yet.

Four of the newly found planets are only about 2.5 times the size of Earth AND they orbit in a region around their stars called the habitable zone. That’s an area of space where conditions are right to allow the existence of liquid water on a planet’s surface. One of the worlds belongs to a star that is half the size and much dimmer than our Sun. That’s the level of detail they’re getting from these observations. And, the discovery of new worlds around other stars is now completely OUT of the realm of science fiction. In fact, I say it’s been out since 1995, when the first one was found. This stuff’s IS real, folks!

So, now, all you budding science fiction writers out there, read the full story on the latest discovery, check out the exoplanets at the Kepler web site and see for yourself that they exist. Figure out from their orbital characteristics just what kind of planets they might be. With that, you’ve got fodder for countless stories to be told. And, that’s a great thing. I’ve always said the universe has great stories to tell — and it just keeps supplying writers with a LOT more places to set them.

By the way, there’s a cool new app out called Exoplanet.  It keeps track of the latest exoplanet discoveries (although as if this writing it hadn’t quite caught up with the latest discovery, but give it time) and gives you lots of data about other-world discoveries. It has in-app purchases that allow you to plug in other functionality, but the main app itself is free. So, if you’re into exoplanets (or want to be), check it out!

It’s Tough out there for an Elliptical

Black Holes Affect the Neighborhood

Galaxies are full of stars, and if a galaxy wants to stay on the cutting edge, it continually makes new ones. We see that in the Milky Way, and in many other galaxies throughout the universe. But, there are some out there that can’t make stars. They have the material to do so, but something is keeping the star-making gases from coalescing to create blazing starry neighborhoods.

A multi-wavelength view of the elliptical galaxy NGC 5044. Credit: Digitised Sky Survey/NASA Chandra/Southern Observatory for Astrophysical Research/Very Large Array (Robert Dunn et al. 2010)

Astronomers using the Herschel Space Observatory have found at least one massive elliptical galaxy called NGC 5044 that has the “stuff” to create stars, but it’s not doing so. A closer look reveals why: a supermassive black holes at the core of this galaxy, and several other ellipticals that have star-making “stuff”, sends out jets which heat up the cold gases that stars need to form. Or, it’s also possible that they stir up the gases, which slows or stops the starbirth process.  This seems to be a problem with elliptical galaxies (those without spiral arms), which are marked by a lack of star formation. For a long time, astronomers thought these old galaxies (which they refer to as “red and dead”) just didn’t have enough gas to continue star formation. Where did it go?  Why did they seem to lose whatever it took to make stars?

Many theories abound:  these galaxies could have expelled all the cold gases that are essential to star formation. Or, maybe they used it all up to make new stars and there wasn’t any left. That’s not an unknown problem in star-forming regions: once a certain amount of a starbirth créche is used up, there’s little left to make more stars. But, a galaxy-wide shortage?  That has been a bit tougher to explain.

So, astronomers looked at eight galaxies using Herschel and its infrared-sensitive detectors. Based on those observations and others, it turned out to be central black holes actively stirring up the galaxies, which affected the gases required to make stars. By looking at these galaxies in various wavelengths of light, astronomers could find plenty of cold gas to make stars. But, the black holes and their jets are messing with the galaxies’ abilities to make stars. In fact, the jets could be pushing the precious gases needed to create stars out beyond the galaxy.

You can read more about this discovery at the Herschel Space Observatory Web site. The study discussed there is based on observations performed with the Photodetector Array Camera and Spectrometer (PACS) on board ESA’s Herschel Space Observatory, as well as optical observations from the Southern Observatory for Astrophysical Research (SOAR) telescope in Chile and archival X-ray data from NASA’s Chandra X-ray Observatory. Such multi-wavelength studies are giving astronomers a much fuller look at objects in the universe, because each wavelength of light tells something unique about what these objects are doing.