Perhaps you’ve seen the video of George Hrab and me performing his song "Death from the Skies". And perhaps you’ve seen my own show, "Bad Universe".

Now, thanks to Dana Peters, you can see them together:

After all, these are the real ways the world will end.

Is the solar cycle shutting down?

New results indicate it may very well be, at least temporarily. Even though the Sun is currently approaching the peak of its cycle in 2013, and we’re seeing an increase in activity (more sunspots, flares, and other violent events), there are strong signs that the next expected peak (in 2022 or later) may be weaker, or may not come at all!

Here’s the deal. The Sun is a seething ball of ionized gas, called plasma, and has very complex magnetic fields that interact with this plasma. The overall strength and activity from the magnetic field rises and falls on roughly an 11 year cycle. When the cycle is at its minimum the field strength is weak, and we see few or no sunspots or other activity. Then, a little over five years later, the cycle peaks and there’s lots of fun stuff going on, with flares, coronal mass ejections, and more.

Scientists studying the Sun have been trying to figure out this cycle for over a century. It’s very complex, but as technology has gotten better, some trends have been found. And recently, these indicators are all pointing to the Sun settling down magnetically.

For one, there is an east/west river of gas the flows under the surface of the Sun (it can’t be seen directly, but it generates sound waves that travel from it to the surface, revealing its presence; I describe this in detail in an earlier post). This river comes and goes, but usually forms at mid-latitudes on the Sun and shifts toward the equator as the cycle progresses. As it does so, sunspots form above it. Although the next cycle won’t start for a few years, the river associated with it should already be forming. However, there are no indications it has, making astronomers think the next cycle may be delayed.

For another, scientists have found that the average magnetic strength of sunspots has been declining over the years. Sunspots form when magnetic fields inside the Sun break through the surface. Normally, rising gas from the solar interior would cool and drop back down, but due to the way the magnetic fields interact with the gas, the cool gas is prevented from dropping. Cooler gas is dimmer, so we see this as dark spots on the Sun: sunspots.

Sunspots are an intrinsically magnetic phenomenon, so this trend of weaker magnetic fields inside them may be indicating, again, the next cycle may be delayed or not come at all.

Moving farther outward yet we come to the third line of evidence of a weak upcoming cycle. The Sun has an atmosphere, called the corona, of very thin but extremely hot plasma. It too is greatly affected by magnetic fields; every cycle the magnetic activity in the corona tends to form near the Sun’s equator and then slowly move toward the poles over the next few years. This "rush to the poles", as the scientists call it, is very weak this year, and may indicate that the peak in 2013 may not be terribly active. It’s unclear what this might mean for the cycle peak after that.

So what does this mean for us? (more…)

Is this the most distant object ever seen?

[Click to deathfromtheskiesenate.]

That is GRB 090429B, a gamma-ray burst (or just GRB to those who want to sound nerdcool), the catastrophic and extremely violent detonation of a massive star. Think of it as a super-supernova, the death throes of a star that lived a short, hot, turbulent life. I wrote about them extensively in my book "Death from the Skies!", or you can get the details about how they form and why they’re so awesome in an earlier post.

Its distance is estimated to be a whopping 13.14 billion light years. If this holds up, it may be the single most distant object ever seen by humans.

But is this really a record-breaker? And why aren’t we sure? OK, this takes a wee bit o’ explaining, but I think you’ll like it. After all, it’s an explosion so big it’ll crush your mind into dust.

[UPDATE: Due to a typo in my math notes early on, I incorrectly said the distance to this burst was 13.4 billion light years. D'oh! I have corrected all the numbers below, and I apologize for the error.]

Boom! goes the dynamite

The important thing here is that they are so bright — emitting more light in a few seconds than the Sun will over its entire lifetime — that they can be seen for tremendous distances. In fact, they can be detected from clear across the Universe, which is where GRB 090429B comes in.

It was first seen on April 29, 2009 (hence the name 090429B — it was actually the second GRB seen that day) by Swift, NASA’s satellite specifically designed to detect GRBs and rapidly transmit their locations to telescopes on the ground. GRBs fade very quickly, in minutes or even seconds, so rapid response is critical. In this case, observations by ground-based telescopes quickly revealed this was an unusual burst. Within hours astronomers began to suspect it was vastly distant. Estimates started putting it at greater than 13 billion light years away, almost as far as an object can be in the distant Universe.

Far, far away

Frustratingly, clouds prevented the monster Gemini 8-meter telescope from getting a spectrum of the burst, which would have nailed down its distance. Without that, the distance can only be estimated. However, several factors indicate it really is at this extreme distance:

(more…)

The Carina nebula is a sprawling, monstrous complex of gas located a mere 7500 light years from Earth. Hundreds of light years across, it’s massive enough to create thousands of stars like the Sun. Tens of thousands.

And churn out stars it does. Embedded in the nebula are several clusters of newborn stars, and many of these stars are so massive they’re nearly at the limit of how big a star can be without tearing itself apart. Stars that big explode as supernovae, and a new mosaic by the orbiting Chandra X-ray Observatory indicate they’ve been popping off in the nebula for quite some time:

[Click to enchandrasekharlimitenate.]

This image is pretty amazing: it’s a mosaic of 22 separate images by Chandra, covering 1.4 square degrees (seven times the area of the full Moon on the sky), and represents an exposure time of 1.2 million seconds! Since it shows X-rays coming from astronomical objects, it’s false color: red is from lower energy X-rays, green is medium energy, and blue from the highest energy photons.

The diffuse glow is from two sources: the stellar winds from those massive stars slamming into surrounding ambient gas at high speed, and from the shock waves generated when supernovae explode. Both are extremely high-energy events, and produce copious amounts of X-rays. That long, horizontal arc is probably the edge of a bubble, a shell of gas piled up from the winds of stars and supernovae like snow piled up in front of a snowplow.

That’s evidence right there that Carina has been cranking out supernovae over the past few million years. Interestingly, it’s what’s missing that provides more proof. (more…)

Yesterday, I wrote about a new study that indicates that free-floating planets in the Milky Way may outnumber planets orbiting stars, and even be more numerous than stars themselves. It’s an amazing result! The most likely scenario is that these planets formed in solar systems similar to ours, but got ejected due to gravitational interactions with other planets in the system. These planets get literally tossed out into space, wandering the galaxy forever^*.

This made me wonder: if these numbers are correct, how likely is it that such a rogue planet might actually be close by on a cosmic scale? And given the kind of topic I like to write about, are we in any danger from a close encounter with one of these galactic nomads?

These wandering planets are so dark and distant they are currently essentially impossible to detect using regular techniques, so we don’t know if any are in our galactic neighborhood or not. The only way to get a grip on how close one might be is to look at it in a statistical sense: on average in the galaxy, how many of these planets are there per cubic light year of space? Then we can fiddle with the number a bit to see how far away one of these planets could be.

Let me be clear up front about something. No doubt there will be people who may want to claim these rogue planets might explain Nibiru or Planet X or the Mayan apocalypse. These people are wrong (again, and as usual). As you’ll see, the math absolutely does not support such a claim at all. So if you hear someone talking doomsday, send ‘em here.

And I might as well address the TL;DR crowd: the conclusions I draw here are that a) on average, a rogue planet may be closer than I would’ve initially guessed, but 2) not nearly close enough to be a concern in any way.

OK then, got it? Onward to the math!

Crank up the volume

Basically, all we need to do is take the number of rogue planets in the galaxy and divide it by the volume of the galaxy, and that gives us the density of these planets in space: how many there are in a cube a light year on a side. If the answer is, say, 1 then we expect to have one rogue planet inside a one-light-year-wide cube centered on the Sun. So let’s see what the math tells us.

(more…)

When I was at the Northeast Conference on Science and Skepticism (NECSS) in April, my epidermically bepated pal George Hrab and I performed an acoustic version of his song "Death from the Skies", based on my book. We actually did it twice; once at a bar where Geo was playing with his trio, and again at the conference to close the whole thing out.

People seemed to like it. Geo certainly did, so much so that he wanted a nicer version to release. He therefore did such a thing and made it available to you, the science-loving throng out in the vast BA sphere of influence. He included the song in Episode 212 of his Geologic Podcast, and the skeptilicious^TM MsInformation put it into a feed of its own for you to download and keep in your digital music storage device.

I love both the original version of the song with its funky beat, but I also love this new version. The tongue-in-cheek lazy Sunday feeling of the soothing music coupled with me talking about the statistics of getting wiped out by a gamma-ray burst appeals to my sense of irony. Hope it does yours, too!

And go buy his album. It’s great.

Image credit: Terry Robinson’s Flickr Photostream

This week’s episode of the SETI radio program "Are We Alone" is up, complete with my semi-regular contribution to the segment "Skeptic Check". The show’s theme is apocalyptic scenarios real and imagined, so astronomer Seth Shostak and I talk about various forms of both. Supernovae, gamma-ray bursts, slamming into molecular clouds, the death of the Universe, and of course the Mayan 2012 end times-o-rama.

The whole show is pretty cool, so go check out the Are We Alone page, or if you’re impatient you can just directly download the MP3.