All Space Considered, Jan 2015 Pt. 3 (Beyond)

Quasars Are Aligned

Quasars are black holes at the edge of our observable universe that are very actively consuming material.  They are the most luminous objects we know of, outshining entire galaxies and even supernovae.  A well-known feature of black holes is the "event horizon," the point at which there is no escaping the gravity of the black hole.  Until you reach that point, there is hope of escaping and the closer you get, the more turbulent things are.  A quasar's extreme brightness comes from all of the particles escaping that turbulence getting spewed into a concentrated beam, which looks a little something like this:

It was discovered that the axes of many quasars are actually aligned, despite being separated by billions of light-years.  That separation should make it impossible for them to affect each other, suggesting that something early in their formation led them to be aligned.  An even more remarkable discovery is that they are not just aligned with each other, but aligned with the large-scale structure in their local region.  At very large spatial scales, the Universe does appear to have structure.  Stars and galaxies are not uniformly distributed, but clump along filaments.  The quasar axes seem to be aligned with the filaments.  This is not as yet predicted by our numerical models, so there must be something at work beyond our current understanding.

Fine Structure Constant is indeed Constant

There has been debate amongst physicists as to whether the fine-structure constant is indeed constant.  Just like gravity has Newton's constant that determines how strongly massive objects attract, electromagnetism has the fine-structure constant to determine how strong charged particles attract or repel.  Like with methane on Mars, there seemed to be an observation that showed the fine structure constant actually changed over the course of the Universe's lifetime, but there wasn't enough data to generate certainty, then others proposed alternate explanations, etc.

Well, the most recent set of data seems to indicate the fine-structure constant has not changed over a significant portion of the Universe's life.  Apparently, by looking at the light from a quasar after it has slipped past galaxies at varying distances, we can deduce the fine-structure constant at the time the light passed by the galaxies.  In the case of the most recent study, the galaxies were 8, 9 and 10 billion light-years away, indicating the fine-structure constant hasn't changed in 10 billion years.  The authors of the paper, in typical scientific fashion, noted that this doesn't close the door on the possibility of the fine-structure constant changing, only imposes much stricter limits on how much it might have changed.  It does rule out much of the larger shifts previously proposed.

Black Holes Can Be Ejected During Galaxy Merger

While generations of humans have stared at what seem like unchanging heavens, the fact is the Universe is a very dynamic place.  One of the more dramatic examples of this dynamism is when galaxies merge; and one of the more dramatic things that can happen when galaxies merge is one of the central black holes can be ejected from the merged galaxy.  Check out this here video.

This is like intergalactic bumper cars and it's very impressive that a simulation can match observation so closely.  Once again, in good scientific fashion, the authors of the study are quick to note there is an alternate explanation involving an ultra-large star going supernova.  Generally, supernova fade over a few years, so the persistence of this object seems to favor the black-hole-bumper-car theory.  Even for the largest of stars going supernova, the explosion should fade over the next few years, so we should find relatively soon if that is a possibility.

Binary Star Formation Imaged

ALMA took some images of a binary star system and this is what it saw.

Well, what's over there on the left is what was seen.  On the right is a simulation.  It may not look like much, but it is our most detailed view of binary star formation.  Our understanding of single star formation such as our sun is pretty advanced.  However, our understanding of binary star formation is not quite as mature.  From the many images captured of this system forming, it appears that gas is indeed falling in to the two stars, leading to the relatively empty inner ring.  This is no different from single star formation.  What's different is the shape of the circumbinary disk.  With two stars pushing and pulling on the gas within that disk, it is far from radially symmetric, like the planet-formation seen in this other image from ALMA (which has nothing to do with star formation, but is pretty).

All Space Considered, Jan 2015 Pt. 2 (Solar System)

Methane on Mars

There has been some debate as to whether there is methane on Mars.  Some Earth-based observations seemed to indicate quite clearly that there was methane on Mars, but there was still doubt due to possible alternative explanations.  Curiosity has more or less ended the debate, detecting methane in high enough concentrations to conclude that Mars itself is the source.  Methane gas is very transient, destroyed by UV rays constantly coming in from the sun.  For the levels to be so high, there had to be a source on Mars itself.  The significance of methane is that biological life is a strong contributor to Earth's methane levels.  Bacteria release it as a waste product from the guts of millions of animals everyday.  However, there are geological sources of methane as well, so we can't quite say "Life on Mars" yet and unfortunately Curiosity doesn't have the instrumentation to answer definitively.  However, it will likely be a major component of future missions to Mars.

The above map shows the methane concentration on Mars, with red being the highest levels and purple being the lowest.

Water Sampled By Rosetta

Rosetta is the satellite orbiting comet 67P, Churyumov-Gerasimenko.  It dropped Philae on the comet's surface back in November and is continuing to collect data about the comet.  From that data, it has been determined that the water on the comet is very different from the water on Earth.  It is widely speculated that Earth's water came from comets in the distant past.  However, if that were the case, the general character of the water should match what we find in comets.  Water can be differentiated by the concentration of heavy water (water that has a neutron in one or both of its hydrogen atoms).  Comet 67P's water has a much higher concentration of heavy water than the water on Earth.  This suggests that Earth's water came from asteroids rather than comets, but it is only one data point in a fairly big picture.

The above graphic shows just how high the levels measured by Rosetta are in comparison to Earth's water.  However, many other bodies have been analyzed and found to be a much better match.  As more data comes in, we should be able to generalize which class of bodies contributed the most.

Atmospheric Rivers

California got a lot of rain in December.  This was due to what is known as an "atmospheric river."  There is always a high concentration of airborne water around the tropics.  Occasionally, wind conditions are such that this moisture is swept north.  Once the airborne moisture hits land, the water cools, condenses and falls to the earth, a process known colloquially as "rain."  In case my words weren't clear, here's a picture showing why they call this thing a river.

The reason such terrestrial phenomena are so important to astronomy is that they help us understand what happens elsewhere.  By extrapolating what we know about how such systems operate on Earth, we can improve our understanding of observations of other planets, other moons and perhaps even dwarf planets.  That, in turn, helps us target places not only to search for life, but possibly to colonize ourselves as well.

CIA Tweets About UFOs

The fact that one of the most secretive agencies in the government Tweets is sort of news unto itself.  Not so surprising is that the Tweets tend to be about events in the 50s.  Okay, the 70s too.  In this recent tweet, the CIA admitted to flying secret reconnaissance missions at altitudes much higher than a standard airliner.  Specific flights correspond directly to UFO sightings by pilots and others during the period 1954-1974.  Now, if only they'd tell us what Roswell is all about.

All Space Considered, Jan 2015 Pt. 1 (New Horizons)

Attendees of All Space Considered this past Friday (the first ASC of 2015) were treated to Alan Stern, Principal Investigator of the New Horizons mission.  He teleconferenced in from his home in Colorado and told us all about the mission.

New Horizons is humanity's first trip intended to study objects beyond the outer solar system.  It is going to Pluto and will study both Pluto and its moon, Charon.  The term "outer solar system" is traditional and loosely means the gas giants.  With the discovery of multiple objects in the Kuiper Belt  as well as continued discovery of long-period comets, it has become clear that there are entire populations of objects orbiting the sun beyond Neptune, not just Pluto.  That discovery is what pushed New Horizons into existence.  Despite decades of work by various scientists to get a Pluto mission funded and approved by NASA, it was only after direct observation of other Kuiper Belt objects that New Horizons was, in fact, approved.

Stern's appearance coincides with New Horizons having woken up out of its final sleep on approach to Pluto.  That happened on Dec 6 and everyone is now looking forward to the six months of observations New Horizons will make, beginning in February.  The closest approach to Pluto will be on July 14, but a full 10 weeks before that, the images New Horizons takes will begin to exceed the resolution of our current best images, primarily taken by the Hubble Space Telescope.  Stern mentioned that an image of Earth at the same resolution as our current best Pluto images would not even resolve the continents.  The best pictures from New Horizons, on the other hand, will be able to resolve features on a human scale.  His exact words were, "If we were looking at Earth, we would be able to see the ponds in Central Park."  We will, of course, get similar data on Charon.

The reason New Horizons will only be observing Pluto for six months, unlike Cassini at Saturn or Curiosity at Mars, is that it is a fly-by mission like the Voyagers.  Pluto doesn't have enough gravity to capture the satellite, which has to travel at fairly extreme velocity to get there in a reasonable time.  While it would be really nice to be able to orbit, flying past Pluto introduces the possibility of studying other Kuiper Belt objects.  Two objects have been identified by Hubble, but Stern was very clear that the selection of that target will not happen until August or so, not wanting to distract his team or compromise the collection of data at Pluto.

New Horizons will provide us with our best data of the Universe beyond the outer solar system.  This will provide us with information on how our solar system formed, how systems might form around other stars and, ultimately, how that whole story might lead to habitability on other stars.  And, as always, simply doing the science will lead us to whole new questions we didn't even know to ask before.  I think I speak for everyone in the audience at All Space Considered in expressing gratitude to Alan Stern and the staff at Griffith Observatory for giving us a glimpse into New Horizons, Pluto and our Universe.