Archives For astronomy

alien liftoff

Imagine a relatively ordinary white star much like our own, because despite appearing yellow in our skies, it’s actually bright white. Now, increase its size by half and add a pattern of dimming when observed by planet-hunting telescopes which blocks up to a fifth of its light in uneven and eyebrow-raising events. Whatever is causing them can’t be a planet, but it can’t exactly be dust clouds from early planetary formation because this star is is a mature one. Believe it or not, this star exists and it has a name of sorts: KIC 8462852. It’s the talk of the Planet Hunters forums, a collection of people who volunteered to analyze data on some 150,000 stars to help find transit events, that is, the dimming of a star’s light when a planet passes in front of it. For six years, no one has been able to figure out its patterns of irregular dimming every two years until a team of astronomers finally came up with the idea of alien comets being pulverized after the star pulled them into its orbit, releasing vast clouds of gas and dust able to produce these dips in light.

Although the explanation isn’t airtight, the general consensus is that it’s the best we can do for now with the information we have and that more observations will be needed to confirm this. At the same time, however, science editor and writer Ross Andersen decided to get a tad creative and talked to the paper’s lead author, Tabetha Boyajian, to see if the team had any other ideas to explain these odd dimming patterns, then followed up with an astronomer at Penn State who shares her opinion that as big of a leap as it sounds, we couldn’t completely rule out aliens. It’s really a matter of timing. Despite swarms of comets colliding and depositing gas and dust into a solar system being a fairly normal event, the odds of it happening exactly at a time when we will spot it around a particular star is quite low because the debris would be quickly consolidated by both its orbital motion and the gravity of the star. And this means that KIC 8462852 could be an interesting test for an idea long floated by SETI that advanced alien civilizations could be using space solar with a modified Dyson Sphere to efficiently power their orbital infrastructure.

Now, while this is intriguing, there’s still the question of just how likely this explanation is since it requires a few major assumptions the exocomet hypothesis doesn’t. Lucky timing is not exactly the same as positing that a currently unseen planet is home to an intelligent alien species that’s centuries ahead of us from a technological standpoint to build a space solar grid, or could have instead built a kind of semaphore to attract the attention of nearby species. This species would have to be space-faring, fairly mature, resource rich, and not mind that another intelligent alien race would be able to figure out that it exists and where, certainly realizing that anyone looking for intelligent life would find seemingly unnatural dimming patterns of their home star a point of interest just like we have. By contrast, comets careening across the cosmos being drawn into a solar system in the last few thousand years just by chance is very likely, especially considering that if volunteers at home didn’t notice the data anomaly, we’d have missed this oddity. Maybe we are staring right at the proof of intelligent aliens we long sought, and it would be great if that was the case. But if I were gambling on the outcome, I’d put my money on exocomets…

galaxy in hands

We all know that our vast universe is lousy with galaxies. Trillions of trillions of the things sprawl across the known cosmos and more than likely, the unknown one as well. We know a lot about them, including how many of them form. Enormous halos of dark matter and gas collapse into a massive black hole that consumes the matter spiraling around it, producing a bright quasar that takes eons to cool off and settle into a quiet, normal, mature galaxy that prefers a nice nap to a billion year rave under the blazing light of superheated plasma, and has a diversified portfolio of stars that will come and go until the last one flickers out of existence many epochs from now, as the second universal dark age begins. But often times, when astronomers look back toward the earliest galaxies, they find plenty of seemingly fully grown, mature galaxies among the quasars, something that technically shouldn’t happen if all galaxies come from halo collapse events.

But if galaxies don’t start with a bang, how would they accumulate their heft? Well, they’d simply accreate it from relatively cool gas flowing into them from the structure of the universe itself. As these jets of gas flow away from existing galaxies and are pushed by massive energetic events, they can eventually funnel down into a proto-galaxy with a lot of angular momentum, sending it spinning and quickly accumulating more and more matter. While this sounds like a very hot and tumultuous process, it’s actually anything but. The filament feeds dark matter and gas at steady rates and the spin it imparts is barely faster than what’s typical for a mature galaxy. Known as a cold flow model, it explains why some galaxies appear to have aged before their time, a factoid used in many speculative cosmology papers and blog posts to question the age of the universe to imply it was much older than we think. These early galaxies did not actually age quickly, they were still quite young. They simply didn’t have a violent birth and didn’t need to stabilize.

Even though this model has been around for a long time but we’ve never been quite sure if it’s happening in the wild. Until now, when a team of astronomers at Caltech saw a disk of gas and dust some 400,000 light years wide nearly 10 billion light years away steadily fed by a cool gas filament just the model predicted. Not only do we have a good explanation for the discrepancy between early galaxies, we also have direct observational evidence that the theory is correct. A few hundred million years of steady feeding and this galaxy will grow into a huge, stable wheel that looks as if it’s been around for at least an order of magnitude longer than it has, evidence that the universe’s biggest and most important structures don’t always have to be born from an immense cataclysm but gentle nudges from gravity and enough time can do the trick. But we’re not yet done with the cold flow model. Now that we know that the basics are right, we can flesh out exactly what happens when cool gas filaments fuel star birth how they affect the distribution of those stars infants. But that’s space for you. There’s always something more to discover…

asteroid impact

Unlike you see in the movies, no one will be rushing to save the Earth at the last minute with no budgetary or logistical constraints when we detect a killer asteroid headed towards us. Instead, there are dedicated people worldwide who have the tools and the funding to map asteroids that could do some real damage, keep track of their trajectories, and give us early warnings so we can divert or even destroy them should they start falling towards our planet. However, it’s not a lavishly funded or properly staffed group to put it mildly, which is why Motherboard’s profile of it comes off in such an unflattering way, calling it disorganized and inadequate. While I’m positive that the NEOO isn’t going to argue that considering their mission to very literally save the world, they’re given lofty goals and meager cash. But what it will debate is the notion that it’s somehow disorganized. We went from zero situational awareness to tracking half a million objects in only ten years, and to say that having a whole lot of possible impact mitigation plans is anything but reflective of the challenges involved, seems like fishing for justification for a click-bait title.

Pretty much any primer on preventing asteroid impacts could tell you that every asteroid is very different, which means that the same exact technique will have a completely different effect on different asteroid types. Attaching rockets or mass drivers to randomly tumbling rocks could all too easily accelerate an impact rather than prevent it. Drilling into iron rich asteroids, which are more or less just solid pieces of metal, would result in a broken drill. Nuking a rubble pile would send radioactive buckshot raining down on Earth with apocalyptic results straight out of a sci-fi horror movie. What some writers rush to call disorganized or haphazard, are actually just sober attempts to amass an impact mitigation toolkit that would give us multiple ways of dealing with a stray asteroid about to hit us, and tailor detailed plans for each asteroid type. We want to push comets and large, steady asteroids out of the way, nuke metallic asteroids into safe orbits, and capture and re-direct rubble piles through gravitational assists or even inflatable craft, testing all these approaches as thoroughly as possible to make sure they’ll actually work in a crisis.

Now, because the science is still being worked out and we’re not quite sure how the spacecraft testing these methods should work down to every detail, it’s going to take a while to get them in orbit around target asteroids. Throw in typical manufacturing delays and glitches to fix, and the timelines look abysmal. If the NEOO had more money, it could move faster, but even then, we’d have to deal with the fact that not every mission would be successful because, again, we’re still learning how all of this will work. So far, we know kinetic impactors definitely pack a good punch as seen with the Deep Impact mission. We also know we have the know-how to land on comets and asteroids, as Rosetta and Philae demonstrated. We’re on the right path towards being able to defend ourselves from another K/T event, like the one that gave the dinosaurs what is one of the worst weeks the planet has ever seen. And while we do need more money to test our ideas out in the real world, there seems to be real progress in getting it, hiring more staff, and figuring out how to track more objects. Unlike some writers would have you believe, it’s actually starting to come along and politicians are taking it seriously enough to open up the funding spigots.

cosmic mesh

Dark matter is a substance that makes up nearly all mass in the universe, but decades after we discovered it, all we have are indirect measurements which show us that it’s there in very large amounts, forming galactic halos, but ultimately, little else. It doesn’t seem to interact with any of the stuff that makes stars, dust, and planets, it emits or reflects no radiation, and this utter lack of interesting properties we could study leads to much wailing and gnashing of teeth on physics blogs and forums, wondering if it even exists. But there might finally be a glimmer of light in the study of dark matter because there’s now evidence that it can interact with itself and matches at least one theoretical behavior. While that doesn’t sound like much, it’s actually a pretty big deal because it narrows down the possible culprits and shows that we can design some way to catch particles exhibiting this behavior to figure out this mystery once and for all. Hopefully.

Last year, a team of researchers was examining the Bullet Cluster, which is actually two galaxy clusters undergoing a series of violent collisions, to try and detect dark matter interactions and figure out to what, if anything other than gravity, dark matter responds. The observations were not exactly conclusive, but they didn’t completely rule out dark matter particles colliding, just set a bound in which they can be expected to collide. Armed with this data, the same team tried to catch a glimpse of interacting dark matter particles in a cluster of just four galaxies, Abell 3827, hoping to get more detail how their galactic halos behave during tidal stripping events. Despite sounding like something like something one galaxy does for another to keep things interesting and relieve a little stress, it’s actually when galaxies shed stars, gas, dust, and dark matter to larger galaxies which exert powerful tidal forces on them across millions of light years.

Now, during tidal stripping, there’s a lag between matter being absorbed into a new galaxy and more matter coming in from the old galaxy because as clouds of dust and gas collide, they heat up, producing radiation, and create drag that pushes incoming material back. One inconclusive observation says it may have detected odd gamma ray flares that could be dark matter colliding during this phenomenon, but since no others have, some cosmologists concluded that it means that dark matter doesn’t interact with itself. But the team observing Abell 3827 found the tell tale signs of a significant lag in dark matter halos with a rate of interaction which fell neatly into their previous results. This means that dark matter particles are colliding, creating shockwaves and a detectable lag between absorbed and incoming clouds. In fact this lag can be up to 5,000 light years which isn’t much on a galactic scale, but definitely big enough that it’s unlikely to be just a fluke, or a random artifact in the data. Finally, we know something new about dark matter!

Of course we still don’t know what it really is, but we can now rule out a whole host of extremely exotic candidates which can’t interact with each other, and start designing detectors to seek out even more such events to confirm the observation and gather more data. With each new piece of information we tease out, we can eliminate more and more culprits until can actually design a way to capture dark matter itself. It may take decades more until we get to that point, but like a punishing, extremely difficult game can give you immense satisfaction when you finally manage to figure out the rules and advance, so can a profound and difficult to solve mystery like finding out what dark matter really is. Maybe it will be nothing groundbreaking in the end, and maybe it won’t change anything we think we know about the universe, but just the fact that we persisted, observed, experimented, theorized, and then observed some more to figure it out should make us a little more proud of our species in general for not giving up on a very difficult question.

See: Harvey, D., et al (2015). The nongravitational interactions of dark matter in colliding galaxy clusters Science, 347 (6229), 1462-1465 DOI: 10.1126/science.1261381

Massey, R., et al. (2015). The behavior of dark matter associated with bright cluster galaxies in the core of Abell 3827 MNRA, 449 (4), 3393-3406 DOI: 10.1093/mnras/stv467

[ illustration by AYM Creations / Ali Yaser ]

radio telescope

Well, as you were warned, Weird Things is back in action, coming to you from Los Angeles with the latest in high tech, astrobiology, strange, bleeding edge science, and skepticism, and I can’t think of a better way to return than with tackling an alien contact story that spread across much of the web like wildfire, appearing in everything from IBI, university blogs, Forbes, and featured by the usual suspects like New Scientist. According to this story, fast radio bursts, or FRBs, are not actually the bizarre, millisecond-length death cries of distant exotic neutron stars collapsing into black holes, as one of the front-running hypotheses states, but may be aliens trying to ping our radio telescopes to see if we’re out there and listening. Think of them as a Wow! Signal on repeat, something not giving us much to work with, but ultimately fascinating by the possibilities they offer, in one of which, SETI’s Seth Shostack sees the work of his alien colleagues…

These fast radio bursts could conceivably be ‘wake up calls’ from other societies, trying to prompt a response from any intelligent life that’s outfitted with radio technology.

But what exactly makes these FRBs so special that someone would even consider them as the work of an intelligent mind? It all comes down to a number called a dispersion measure in radio astronomy, the density of free electrons affected by the signal on its way to our receivers. This might not tell you exactly how far away a radio source is, you’ll have to do some work to adjust your measurements for what’s known to exist in the direction from which you’re getting a signal to do that, but it does tell you something about the distance and power of the object. And when one cluster of FRBs was recently observed in real time, this measurement consistently came in as some multiple of 187.5 which, according to the experts, has a 1 in 2,000 chance of occurring naturally. This is not a wandering, random signal we happened to pick up. There is a very clear and distinct pattern.

Of course all this doesn’t mean that we have a slam dunk case of alien contact because we’ve already gotten some very steady, regular pulses the distance and location of which we did pin down to fixed points in space, unlike FRBs. We also wondered if these were otherworldly minds trying to see if there was anyone out there because the pings were so regular, predictable, and clear, also unlike these FRBs. Now, when we get such regular signals, we know it’s a neutron star with a powerful magnetic field pointing at us, not a distant alien civilization saying hello. A pattern in a signal doesn’t necessarily mean intelligence, even if the pattern is odd. All that was determined so far is that some pattern exists with significant certainty. What’s actually causing this signal is still a mystery, and the best we can do for now to identify a culprit is to say that the FRBs are most likely coming from our own galaxy. So how did we go from basic signal analysis to a deluge of announcements about the possibility of first contact with extraterrestrials?

You see, when the researchers were speculating about what causes FRBs, they spent the vast majority of their time talking about the relationship between the bursts, the pattern they found in the distribution measure, and the Earth’s integer second, a number used for syncing devices to keep very precise track of time. In fact, the explanation they consider most likely involves some sort of a ping between cell towers bouncing around high in the atmosphere, confusing delicate equipment, and the scatter plot of distribution measures show that the signal coming from deep space would either be on the move, or going through a very irregular cloud of gas and dust. So just for the sake of completeness, they add the the following thought…

A more likely option could be a galactic source producing quantized chirped signals, but this seems most surprising. If both of these options could be excluded, only an artificial source (human or non-human) must be considered, particularly since most bursts have been observed in only one location (Parkes radio telescope). A re-assessment of man-made phenomena, such as perytons, would then be required.

They then go on to say that the strong relationship between the detected FRBs and a common timekeeping standard we use in precision equipment pretty much “clinches” the case for a very straightforward explanation that we’re detecting our own electronic noise. So out of a four page paper talking about how likely it is the FRBs are noise form our devices trying to stay in sync to provide us with reliable communication channels, a single speculative mention of “non-human” sources from space which is dismissed in light of the collected evidence turned a summation of some purely technical analysis of radio noise into “we’re being called by aliens!” splattered on a thousand news sites and pop sci blogs. Did no one read the paper? Looking at some dates, it’s possible to find to at least one of the big culprits of this very inventive take on this research.

Bet you won’t act too shocked when I point the finger to the Daily Mail since they’ve done the same sort of thing before, claiming that an astronomer detected signals he didn’t detect from a planet which never actually observed, and it appears they did it again, to be copied by as many other sources as possible to get the traffic. Considering that their journalistic standards are not so much lax as they are completely non-existent, they’re not going to be above warping what a scientific paper says to manufacture news where there really aren’t any. They’re technically not lying as such; the researchers did say that we could consider a non-human artificial sources of the signals they detected. It’s just that the Mail and those rushing to run with the same story in editorial haste just so happened to omit that the researchers followed this thought up with “but seriously, no, don’t, it’s pretty much certainly our own noise” to draw in a few million clicks…


We’ve long known that there was an ocean or something very much like it under the icy crust of the Jovian moon Europa, and that this icy wasteland offers one of the best chances to find life in our solar system despite living in a very turbulent and radioactive neighborhood. And now, the same astronomer who stunned Pluto before the IAU’s planetary double-tap, Mike Brown, found strong evidence that Europa’s ocean is leaking to the surface and is salty like ours. Basically, a short summary of the elegant details I encourage you to read from Dr. Brown himself is that the chemical residues on the moon’s surface match up with exactly what we’d expect if it had a thick, salty, liquid ocean which periodically rises through the cracks in the ice and leaves deposits as it recedes with the tides. We could learn even more, but radiation scatters other compounds we could measure from our post right here on the blue marble. So far, though, so good for bacteria and multicellular colonies that could potentially call Europa home.

Now it’s very important to know that organic chemical signatures do not always mean life and a distinct lack of experience with alien organisms on our part means that until we actually see one with our probes and run several hundred tests and a few thousand reviews of the data from all those tests, we won’t know if we found alien organisms. Well, unless an alien fish just wiggles to the camera and waves hello. That would speed up the announcement. But in all seriousness, as far as cases for promising habitats go, everything we find about Europa makes it look better and better for exploration. The only problem is that the ocean where so much life could exist lies so far down, in some cases under several miles of ice. Drilling through it is complicated and really dangerous for robotic probes, so the focus has been on trying to get access to the ocean with a minimum of digging, using something like a rover with a tiny submarine to explore the shallows. If what Brown has found is any indication, we might find even more about Europa’s chemistry this way since some of the more scientifically interesting chemicals could just float up to us.

However, keep in mind that the moon’s surface is bathed by radiation and microorganisms that evolve under several miles of ice and meters of water would be instantly fried to a crisp if they’re exposed to it, leaving promising but ambiguous residue on the surface. For anything more alien and complex than extremophiles that may have even survived the trip from Earth, we will need to be ready to dive deep and look far and wide. It’s actually another reason for human exploration of the outer solar system. Robots can only be made so clever in space, and they’re not good at dealing with the unknown and the uncertain, having no instinct or useful previous experiences from which to make decisions about new environments. Having humans guide them as they look for alien life on an unknown, largely unfamiliar world would be a terrific fusion of our brainpower and machine endurance that could lead to something as big as proof that we’re not alone. That knowledge alone should justify the effort of making the trip.

[ illustration by Guillermo Krieger ]


Since the dawn of modern cosmology there’s been an implicit assumption that no particular spot in the universe was supposed to be any more special than the rest. On the biggest scales of all, scales at which galaxies are treated like tiny particles, the universe is supposed to be isotropic and homogeneous i.e. more or less uniform in composition and its expansion from the Big Bang. For decades, simulations and observations seemed to show that this was really the case, but as a newly published paper argues, this might no longer be the true because lurking at the dawn of the universe was a group of quasars stretching for nearly 4 billion light years and tipping the very large metaphorical scales at 6.1 quintillion solar masses. That’s a big enough cluster to shatter the theorized limit on how big cosmological structures should be able to get by a factor of four. It looks as if the cosmological principle might need some refining unless it turns out that data from the Sloan Digital Sky survey is wrong and this cluster is much, much smaller than it appears.

Here are the basics on the fancifully named Huge Large Quasar Group, or Huge-LQG for short. It’s made up of 73 quasars arranged like a Y chromosome that was been shot right through the center with a high speed projectile. The upper, crescent-shaped branch is 56 quasars and the remaining 17 cluster tightly right underneath it. It’s about eight times the width of the Great Wall, which was once considered such an enormous cluster of galaxies that it too was once billed as a discovery that would challenge the cosmological constant. But simulations showed that it simply wasn’t big enough and that clusters as wide as 1.2 billion light years still leave the cosmos more or less uniform and isotropic. And this is the major issue with Huge-LQG. It’s almost four times wider and there’s no explanation for how a structure this big could exist without being torn apart by gravity and the expansion of space-time long before it gets anywhere near that size. Now, we can’t exactly toss the cosmological principle away yet, but we at least have to refine it.

Obviously, something is missing and if we were to simply adjust and say that 4 billion light years should now be the new limit on quasar groups, we would be missing why that’s the case. Letting go of the cosmological principle opens us to new models of galactic and cosmic evolution and exciting new ideas. However, it’s not really that simple because we’d also have to explain how an anisotropic early universe became the mostly isotropic, homogeneous mature one we see today while working in the confined space of a finite cosmos. One easy way to stick with homogeneity could be to declare that the known universe must be much bigger than we think because if your scale is big enough, anything can become small enough to be homogenized into your structure, but without being able to see beyond 13 billion light years or so, super-sizing the universe is an extremely questionable proposition. Either way, Huge-LQG leaves us with a dilemma that really gives the status quo a run for its money, and that’s how the really exciting breakthroughs can be made, fascinating new science gets done, and Nobel Prizes are eventually earned…

See: Clowes, R., et al. (2013). A structure in the early Universe at that exceeds the homogeneity scale of the R-W concordance cosmology MNRAS DOI: 10.1093/mnras/sts497


Another day, another study identifying more potentially habitable worlds in the Kepler data, this time by professional astronomers and volunteers called the Planet Hunters who discussed their planet detections on a specialized message board system called Talk. What they found was that more gas giants orbited stars in their habitable zones than initially thought, giving real evidence for the hypothesis that while alien Earths could be somewhat rare, moons orbiting alien Jupiters and Saturns may be a fairly common habitat for extraterrestrial life. Trouble is that we can’t see these moons or detect the wobble of the planets they orbit, so we don’t know how many of them there are, how big they are on average, and their likely composition. However, we do have very good reasons to assume that they could be there since gas giants in our own solar system are swarmed by moons of all shapes and sizes, and some are very possible hosts to life.

So one would think that a moon big enough to hold on to an atmosphere that’s not too dense or composed mainly of greenhouse gases in an alien star’s habitable zone would have liquid water in significant quantities. Even better, it would feel the gravitational tides of a gas giant that would in effect knead its interior, promoting volcanism, circulating rich organic matter that could either kick start living things or fuel them. Think of Io but more subdued and covered with oceans and small continents, or Titan without the mind-numbing cold. It could be a perfect habitat, and given billions of years, maybe even evolve intelligent life. But there’s a potential problem here. Typical solar system formation models dictate that rocky worlds form closer to a star than gas giants, so to be in the habitable zone of the vast majority of stars out there, alien Jupiters had to drift into these orbits, pushing out rocky worlds and reshuffling their siblings. What would that do to their moons? Would they be collateral damage in the upheaval of the solar system?

Ideally, the immense gravity of these gas giants would push planets aside as they spiral into the habitable zone and their clutches of icy rocks would slowly thaw to host oceans and fertile land for life to start taking hold. But again, the only way we’ll know this is if we build bigger and more powerful telescopes to detect their presence and hopefully one day resolve them as pixels for a quick spectrographic sniff of their atmospheres. Maybe, just maybe, decades from now, a future astronomer and a crew of enthusiastic volunteers will be looking through a data set collected by the latest planet hunting telescope and find a little bluish pixel next to a gas giant, or readings of a gas pointing to a stable biosphere, like oxygen from a recently discovered alien moon. It won’t be Earth 2.0, but it will be just as important, and we’ll be able to look up at the night sky knowing that we’re not alone because somewhere, a weird world with a killer view of a turbulent gas giant is home to something that can look back at Earth, even if it won’t wonder about us…

See: Wang, J., et al. (2013). Planet Hunters. V. A Confirmed Jupiter-Size Planet in the Habitable Zone and 42 Planet Candidates from the Kepler Archive Data arXiv: 1301.0644v1

primordial black hole

Usually a new discovery in deep space tends to further complicate our picture of the universe, almost as if the cosmos says "oh yeah, you think you have a good idea of how this works?" and throws a monkey wrench into the works, or sometimes, the whole screaming, angry monkey. So when it comes to phenomena as complex and exciting as black holes, surely there can’t be any data that makes them easier to understand. But this time, when physicists wanted to figure out if jets from black holes followed the same patterns as the mass of the objects went up, nature was willing to cooperate. As it turns out, the powerful jets of material shot from the accretion disks of black holes of 20 solar masses and 20 million solar masses follow the same mechanism. How do we know that? By plotting their strength against the mass of the black hole. If the data follows a linear trend, we know that the physics don’t require a new process to explain the numbers.

So what exactly is happening around black holes? As you may already know, black holes aren’t the cosmic vacuum cleaners far too many sci-fi movies made them out to be. They simply stay where they were very violently born and their immense tidal forces accelerate anything straying nearby into their maws. But black holes are tiny on an astronomical scale and only eat so much at a time. Whatever doesn’t fall directly into their event horizons is whipped around them until it heats up into a glowing accretion disk we can detect. And some of this material gets trapped in the powerful magnetic fields around the black hole and is launched into deep space at 99.9% of the speed of light in the form of highly energetic jets which produce powerful gamma rays. This process seemed to be the same for every black hole observed, but there’s no way to be sure if the black holes affected the jets beyond kinetic energy unless you start comparing gamma ray bursts to one another and plotting them along a trend line.

If the trend is exponential, that means new physics are needed to explain the sudden surges in power as we go up in the jet’s energy and vice versa. But the observed trend between kinetic energy of the jets and the power of the gamma ray bursts is linear, which means that it’s rather likely that the process behind forming the jets is the same across the entire spectrum of known black holes. The black hole’s mass affects how much is can swallow at a time and how powerful the jets it emits could be. The power of the jets affects the observed gamma ray bursts when a new black hole is formed and when it’s in the middle of a large meal consisting of stars and gas floating through interstellar space. So if we know that when we up the jets’ power, we also make the GRB stronger in a predictable way, that tells us that we can more or less confidently scale up what we learn about smaller black holes to their immense siblings, and estimate black holes sizes based on the GRBs’ strength. And that’s very useful for learning more about these prolific and extremely influential gravitational ghosts of giant stars.

See: Nemmen, R., et al. (2012). A universal scaling for the energetics of relativistic jets from black hole systems Science, 338 (6113), 1445-1448 DOI: 10.1126/science.1227416

alpha centauri bb

After decades of trying to find out whether our closest stellar neighbors have planets we could one day explore, we finally have a confirmation that there appears to be an Earth-sized planet floating around Alpha Centauri B. If we wanted to get really nitpicky and technical, this is not the closest star to us because Proxima Centauri is slightly closer, but for practical purposes, this is a world which could well be within our reach in the next 50 to 75 years. Now for the bad news. We probably wouldn’t want to go there because its orbital period is about three and a half days, so its basically a planet like Venus but even more hellish, with a surface of molten rock and little to no atmosphere to speak of, likely stripped away by the stellar winds. Still, this is very good news because there is the potential for more planets in the Alpha Centauri system. We’ve seen plenty of planets orbiting binary star systems, and recently, even a world orbiting a quadruple one. We just need to keep looking for gravitational tugs on the stars in longer orbital periods.

Hold on a second, how come we can find planets orbiting hundreds of light years away but our nearest neighbors’ planet count was and still is an open question? Well, in this case being really close is a big problem because the starlight is so bright that it effectively obscures the planets in transit, making it extremely difficult to detect them with our current fleet of telescopes. Alpha Cen Bb was found by measuring the drag the planet has on its parent star, something easier to see at closer orbital periods since the drag is greater, and thus more noticeable, closer in. For more detail on how this method worked in this case, see the Bad Astronomer’s explanation. His major takeaway from this detection is that we’re getting closer and closer to finding a second Earth if we’re able to find planets close to our mass in more and more places as we keep on looking, so it’s only a matter of time before we spy Terra Nova. And I can certainly agree with that, but it’s a more exciting idea for me to consider more planets around the Alpha Centauri system, ones on which we could land a probe or even a habitat capable of supporting astronauts.

This would give us a good target for the first interstellar journey and help move really ambitious designs to make such a trip possible off the drawing board and into a lab. Of course I realize it’s very unlikely that as soon as a cooler world is found around our nearest stellar neighbors we will be seeing NASA and the ESA start planning missions to it. And I’m pretty sure that we won’t just take astronauts and launch them on a multi-generational trip there. We’re going to be trying the most radical propulsion methods we can conceive of and the humans who will land on exoworlds are going to be extensively modified, both genetically and mechanically. But despite all this, just having a closer target to explore would be a terrific incentive to get the projects started. If we’re only able to land on planets tens or hundreds of light years away, the mission time and its basic requirements go up by orders of magnitude over a trip to our nearest neighbors for a relatively quick look-see. Well, relatively quick on a time scale of a civilization that is..