Hungry, Hungry Black Holes 02.10.12

Black Holes have a way of “eating” anything that gets re­motely close to them. In astronomical terms, we are talking about 100 million miles away or less.

It turns out, these pesky over-eating habits seem to be the answer for some questions regarding recent flares from the gigantic black hole at the center of Sgr (Sagittarius) A*. Closer studies seem to reveal that the black hole is surrounded by a cloud of asteroids and other detritus that is continually swept into its path. As it gets close, it gets torn to pieces by the black hole, and this friction makes the pieces heat up and glow, much like a meteor in our atmosphere, NASA says. A flare is produced as an astronomical burp of sorts, and the cycle of destruction continues.

Image credit: NASA/CXC/M. Weiss.

This is no baby with its first birthday cake, though. Far from it, actually. Needless to say, this monster at the center of our galaxy is getting a lot of attention.

Information credit: NASA

Top 11 in 2011, 12.30.11

2011 has been a tremendous year for astronomy. It has been a marvelous year for discoveries, yet we look forward to the future as the space program evolves to continue without the space shuttles. Here at the Wetherbee Planetarium, we would like to take a moment to reflect on some of our favorite stories we covered this past year.


11. Diamonds in the Sky, originally published 08.29.11. A diamond planet companion was found orbiting J1719-1438. How is that for twinkle?


10. De Blob, it glows!, originally published 08.19.11. Lyman-alpha blob 1 (LAB-1), a giant, intergalactic green blob, was discovered. No one knows what it is, but it is big, it glows, and it is green. We think that is pretty awesome.


9. The sky is falling!, originally published 09.14.11. The Upper Atmosphere Research Satellite (UARS) took a spiraling descent back to Earth over late September-early October, mostly breaking apart and burning in the atmosphere.


8. A Geriatric Non-Planet, Non-Asteroid…Thing…, originally published 04.04.11. The gargantuan asteroid Vesta was visited by NASA’s Dawn mission in July of this year for a photoshoot rendezvous.


7. “Spinstars” May Have Helped Seed the Universe, originally published 05.02.11. Astronomers working with the Very Large Telescope (VLT) theorized the existence of “spinstars,” possibly the fastest rotating objects in the universe.


6. Gamma Ray Flares in Binary Star are a Mystery, originally published 07.07.11. A binary star system in January and February of this year was found emitting gamma ray flares as a companion pulsar grazed through the Be-class star’s gaseous disc.


5. “It’s Alive!” Zombie Satellite Galaxy 15 Springs Back to Life, originally published 01.04.11. Rebellious satellite-gone-rogue Galaxy 15 came to its senses and rebooted after months of failing to respond to commands and joyriding.


4. Life-Friendly Zones in the Galaxy?, originally published 09.30.11. Astronomers theorized the possibility of a “life zone” or area in galaxies that is most likely to support life as we know it.


3. Hubble Celebrates Millionth Observation, originally published 07.12.11. The Hubble Space Telescope made its historic millionth observation of outer space, a spectroscopic observation of planet HAT-P-7b.


2. The Star of Bethlehem, originally published 12.20.10, reprinted 12.20.11. The staff at the Wetherbee Planetarium delved into possible explanations for one of the most iconic symbols of the Christmas season.


1. Launch Week: Last Flight of Space Shuttle Endeavour Scheduled Friday, originally published 04.25.11. NASA set the launch date for the last flight of space shuttle Endeavour, one of the final missions for the shuttle program.


So, what do we expect for 2012? NASA’s Dawn mission will wrap up its study of Vesta, the Russian Phobos-Grunt mission will make its descent back to Earth after its failed launch, Kepler is confident about the odds of finding an Earth-like planet in the life zone, and the biggest non-event: the supposed “alignment with the core of the galaxy” on December 21. Here’s to 2012!

Dwarf planets' fifth birthday, 08.25.11

Five years ago yesterday, the International Astronomical Union demoted Pluto to its “dwarf planet” classification. Here at the Wetherbee Planetarium, that is the single most-heard question we are asked: why? Was something discovered about Pluto that made astronomers second-guess it? Did something happen to it? Not at all. It is the other things around Pluto that made the IAU change their minds about what they classify as a planet, though.

As of August 24, 2006, the definition of a planet by the IAU is: “A body that circles the sun without being some other object’s satellite, is large enough to be rounded by its own gravity (but not so big that it begins to undergo nuclear fusion, like a star) and has “cleared its neighborhood” of most other orbiting bodies.” On the first point, Pluto does orbit the sun. On the second point, as far as we can tell it is relatively round in shape. When NASA’s New Horizons probe cruises by in 2015 we will have close up images of the cold planet for the first time in history and we will know for sure what it is like. On the last point, however, Pluto is not exactly a space hog. It rubs elbows –figuratively speaking—with several other objects in our solar system in a region designated as the Kuiper (pronounced ky-per) Belt, some of which are about the same size as Pluto. 

Pluto is only about 1,455 miles in diameter and only 0.2% as massive as Earth. It is tiny, that much is certain. But, it does have at least four known moons: Charon, Nix, Hydra, and the recently discovered P4 (a dismally boring name, we know—NASA presumes will probably be renamed Cerberus in the near future). In orbit around the sun with Pluto are several other objects about the same size as or smaller. Eris is one such object, and was the turning point discovery that led the IAU to re-think their definition of a planet. Another is Haumea, the rapidly spinning dwarf planet that astronomers guess may have radioactive elements in its core. Another is Makemake (pronounced mah-kay mah-kay), a dwarf planet about ¾ the size of Pluto.

Dwarf planets are not just limited to the Kuiper Belt, though. Ceres, another such object, is actually orbiting in our asteroid belt, between the planets Mars and Jupiter.

Each of these objects misses the criteria for a planet in some way, usually in clearing its neighborhood of other objects. They are massive enough to form into relatively spherical shapes and they do orbit the sun, they just usually are not really big enough to push their way through the crowd and clear their own path.

Credit: NASA.

Playing tag with a "trojan," 08.05.11

Astronomers have recently discovered that Earth is not alone. It seems our planet is being followed, or our Earth is following something else, depending on how you look at it. Earth’s orbit is being shared by an object that astronomers refer to as a “trojan” asteroid.

Thanks to data gathered from the NEOWISE project, astronomers have discovered that there is an asteroid roughly 1,000 feet in diameter that shares almost the exact same orbit as Earth as it travels around the sun. While the asteroid, dubbed 2010 TK7, does at times travel above, below, or slightly to the side of Earth’s orbit, for the most part it seems as if Earth and the asteroid are following in each other’s tracks. 2010 TK7 does travel a little farther away from the sun than Earth does at times, as well.

So, why have astronomers not noticed it until now? It seems that 2010 TK7 is usually difficult to spot because from our vantage point on Earth, it would always appear to be close to the sun. For obvious reasons, this makes it very difficult to observe. The NEOWISE project changed the game though. NEOWISE is an aspect of the WISE (Wide-field Infrared Survey Explorer) mission, a telescope in space far removed from Earth’s atmosphere and the glare of our daylight. The “NEO” part of the name is a side-mission of the probe that searches for Near Earth Objects, bodies that pass within 28 million miles of the sun. By observing 2010 TK7 from outside of our atmosphere, astronomers were able to get a pin point on it and then track it down much easier using other observatories here on Earth, namely the Canada-France-Hawaii telescope on mount Mauna Kea in Hawaii.

Is Earth in danger from its stony stalker? No. According to NASA, trojans are fairly common in our solar system. Neptune, Mars, Jupiter, and even two of Saturn’s moons all have trojans. 2010 TK7 also seems to have a stable orbit, as well, so it is not likely to interfere with Earth.

“It’s as though Earth is playing follow the leader,” said Amy Mainzer, the principal NEOWISE investigator.

Let us hope there are no sore losers in space.

Credit: NASA.

A geriatric non-planet, non-asteroid...thing... 04.04.11

Vesta was discovered on March 29, 1807 by German astronomer Heinrich Wilhelm Olbers. To call Vesta an asteroid is not entirely correct, but it is not exactly a planet either. Too small to even be considered a dwarf planet, it has layers that scientists discovered in 1972 had melted at some point, so it does meet some criteria of being a planet like Mars, Earth, or Venus. Or, at least, a “proto-” or “minor” planet (not quite a planet, like a planet that failed to develop all the way). And, it is tiny.


 Not that tiny, though. It is too large to be an asteroid. Most asteroids are usually only about 60 miles or less across; Vesta is about 330 miles across. Pieces of Vesta (called Vestoids) also orbit with the other asteroids and have reached Earth as meteorites.


In July, NASA’s Dawn mission should arrive to orbit the object for one year, and conduct dozens of experiments in the process. The theory from most astronomers is that Vesta is an object left over from the formation of our solar system, an object that missed out on its chance to join with other bits of rock and dust to form a larger planet. That being the case, astronomers are very excited about the prospect of studying the object with, possibly, the oldest dirt samples. The studies will begin by taking pictures of a massive crater at Vesta’s south pole, and then will orbit northward to study its terrain, surface composition, texture, topography, and gravitational field. The image here is an artistic rendering of how astronomers expect it to appear.

Image credit: NASA JPL.

Credit: NASA JPL.

Asteroid Apophis a threat in 2029? 03.14.11

Astronomers have been tracking a 900-foot wide rock that is hurtling towards earth. Will it strike us? Only the math can tell.

Image credit: SPACE.com.

Photographed on January 31, astronomers said on March 9 that this was the first clear shot they have been able to take of the approaching asteroid in at least 3 years. The photo was taken from atop one of Hawai’i’s dormant volcanoes, Mauna Kea, using a telescope. It was originally thought that the rock had a 1-in-37 chance of hitting earth, but new calculations made the number grow substantially; it now has a 1-in-250,000 chance of dashing earth to bits. Oh, joy!


All of the calculations are made by doing some careful comparisons with the “known” distances of stars near the asteroid. As stars move very slowly, they can be fairly reliable space-scale distance markers, but the passage of time still has to be taken into consideration upon each new measurement. 


If it does not smash into earth in 2029, it should pass by again in 2036 and 2068. The pass in 2029 will likely alter its path, too, making it slide ever so much closer to earth. The pass in 2029, in fact, will most definitely be closer to earth than a lot of communications satellites are! You can expect to see Apophis without the aid of a telescope or even binoculars, weather permitting. Until then, all we can do is sit, measure, and crunch some more numbers.


Credit: SPACE.com.

Geminid meteor shower promises to be year's best, despite mysterious origins, 12.10.10

The Geminids meteor shower has long been considered by astronomers to be the best meteor shower to see. Taking place just a few days before the winter solstice, the cold weather is usually accompanied by high pressure fronts and clear, high-visibility skies. The Geminids themselves usually bring well over 100 meteoroids per hour, and can be seen from any point on the planet. The Geminids are puzzling astronomers though; “they defy explanation,” says NASA’s Bill Cooke.


The problem, he says, is that most meteor showers’ point of origin is a comet. No matter how they do the math on the Geminids, though, the trajectories all point to an object that simply should not be putting off that volume of material: 3200 Phaethon, a “weird rocky object.”


This poses a problem because 3200 Phaethon is currently not shedding much debris at all. The way meteor showers usually work is that earth passes through a dust or debris field left by comets, and the debris is burnt up in our atmosphere as we pass causing streaks or “shooting stars” in the night sky. According to NASA Science, the Geminids are the “900-lb gorilla of meteor showers,” yet “3200 Phaethon is more of a 98-lb weakling.” It simply does not add up.


NASA discovered 3200 Phaethon in 1983 using its IRAS satellite and, according to NASA, “promptly classified it as an asteroid.” Astronomers believe the Geminids originate from debris that is left over from an orbital point when 3200 Phaethon was close to the sun. Astronomers believe the heat from the sun may have caused some dust and debris to have been blown off the side, and this is what causes the Geminids every year. This hypothesis was further strengthened last year during 3200 Phaethon’s observation by NASA’s twin STEREO spacecraft. While extremely close to the sun, “3200 Phaethon unexpectedly brightened by a factor of two,” the only explanation being that it was ejecting material in response to a surface breakdown and reactions within its crust of possible moisture to the intense solar heat waves. Quite simply, it got too close to the sun and started to blow up (or blow off, really).


The best time for observing the Geminids this year is probably between 12-7AM on December 14^th. Gemini should be directly overhead as a good starting place to look. Thronateeska’s Jim Friese recommends going outside the city to a rural area with less atmospheric light pollution and an open sky view. Thronateeska Heritage Center wishes you happy hunting, and be sure to bundle up!


Credit: NASA Science.

Save the planet: task force recommends the creation of a planetary defense coordination office to combat asteroids, 11.03.10

A recent report was submitted to the NASA Advisory Council by the Ad-Hoc Task Force on Planetary Defense that called on Congress to allocate additional funds above and beyond NASA’s annual budget for planetary defense. The threat? Asteroids.

An artist's rendition of an asteroid crashing into Earth. Image credit: SPACE.com.

The report recommends that NASA and the US government take steps toward establishing a Planetary Defense Coordination Office that would cooperate with other national governments for the deflection and/or destruction of asteroids that are on course to collide with Earth. In light of all of the natural disasters that seem to be plaguing Earth as of recent years, former astronaut Russell Schweickart says that “Happily, in the instance of asteroid impacts, this is a natural disaster which can be prevented.”


The task force made five recommendations to the Council that they should “Organize for Effective Action on Planetary Defense,” “Acquire Essential Search, Track, and Warning Capabilities,” “Investigate the Nature of the Impact Threat,” “Prepare to Respond to Impact Threats,” and “Lead U.S. Planetary Defense Efforts in National and International Forums.”


The projected start up cost of the project is $250-$300 million every year for the next decade. Annual operation costs after that are expected to be a comparatively minor $50-$75 million.


The program is intended to detect celestial bodies at least 240 feet wide and deflect them away from Earth, if their projected path places them on a collision course. The task force said the “driving philosophy” behind the program is to “find them early.” While the recommendations did say that the new Planetary Defense Coordination Office would be capable of detecting threats at least a decade before they are supposed to make contact with Earth, NASA and the U.S. government are not obligated to act on their recommendations.


Credit: SPACE.com