The Coma galaxy cluster is unique among known clusters because it contains two giant elliptical galaxies at its center. And recent news shows that this cluster may have other features we don’t see elsewhere.

Galaxy clusters, collections of galaxies bound together by gravity, occur throughout the Universe, and as clusters go, the Coma cluster is one of the largest. It contains over 1,000 galaxies, with more to be identified!

All these galaxies reside inside a giant cloud of hot, energetic gas. Astronomers using NASA’s Chandra X-ray Observatory and ESA’s XMM-Newton to observe Coma discovered huge arms of hot gas over half a million light years long.

Using the speed of sound in hot gas and the gas arms’ length, astronomers calculated the gas to be over 300 million years old! Oddly, the gas in the Coma cluster has a smooth profile, without the lumpiness astronomers expect to see in an active galactic environment. Usually galactic mergers generate significant turbulence that stirs up local gas, but this cluster seems to exist in a relatively calm environment.

This new finding, published in the journal Science, offers insight into how the Coma cluster grew from the mergers of smaller groups of galaxies. As the galaxy groups move through space, head wind strips their gas away, which later forms the giant gas arms we see now.

The multimillion-degree X-ray emission shows that the arms appear to be connected to galaxies far from Coma’s center. At least one of these arms also appears to be connected to a larger structure 1.5 million light years away. It seems that Coma’s tentacles reach for into the cosmos.

Clues hidden in the gas will tell us more about this one-of-a-kind cluster, so stay tuned!

Alyssa Keimach is an astronomy and astrophysics student at the University of Michigan and interns for the Morrison Planetarium.

Image: NASA/CXC/MPE/J.Sanders et al, Optical: SDSS

Here’s a round-up of recent science headlines we didn’t want you to miss!

Ancient Rivers

Without a smart phone or GPS device, how did early humans find their way out of Africa? A study published last week in PLoS One determines that ancient rivers, now covered by the Sahara Desert, provided habitable routes to follow.

Simulating paleoclimates in the region, the researchers found evidence of three major river systems that likely existed in North Africa 130,000–100,000 years ago, but are now largely buried by dune systems in the desert. When flowing, these rivers likely provided fertile habitats for animals and vegetation, creating “green corridors” across the region.

“It’s exciting to think that 100,000 years ago there were three huge rivers forcing their way across 1000-km of the Sahara desert to the Mediterranean—and that our ancestors could have walked alongside them,” says lead author Tom Coulthard of the University of Hull, UK.

Cosmic Beginnings?

Did life on Earth hail from Mars, as one researcher proposed last month, or comet collisions? Apparently, in both cases, it all has to do with the chemistry. Carl Zimmer, one of our favorite science writers, has a recent New York Times article about the chemistry needed to produce DNA from RNA. And while it doesn’t look like early Earth had those compounds, Mars might have.

Then, earlier this week, a study published in Nature Geoscience finds that the collision of icy comets with planetary bodies could result in the formation of complex amino acids, the building blocks of proteins (and life).

The researchers suggest that this process provides another piece to the puzzle of how life was kick-started on Earth, after a period of time between 4.5 and 3.8 billion years ago when the planet was being bombarded by comets and meteorites.

The team made their discovery by recreating the impact of a comet by firing projectiles through a large high-speed gun. This gun, located at the University of Kent, uses compressed gas to propel projectiles at speeds of 7.15 kilometers per second into targets of ice mixtures, which have a similar composition to comets. The resulting impact created amino acids such as glycine and D- and L-alanine. Sounds like a fun method of discovery…

Speaking of fun collisions, if you want more of them, the Morrison Planetarium at the Academy is featuring Cosmic Collisions in its current show rotation. From the our website:

Creative and destructive, dynamic and dazzling, collisions are a key mechanism in the evolution of the Universe.

Missing Mars Methane

One chemical Mars seems to be missing? Methane. The gas was sought as a possible sign of microbial life currently living on the seemingly barren world. However, despite earlier reports that NASA’s Mars rover, Curiosity, discovered methane on the red planet, NASA reports today in Science that none has been found.

Curiosity’s earlier evidence of methane detection turned out to be within leftover air from Earth. And previous reports of localized methane concentrations up to 45 parts per billion on Mars were based on observations from Earth and from orbit around Mars.

“It would have been exciting to find methane, but we have high confidence in our measurements,” says the report’s lead author, Chris Webster. “We measured repeatedly from Martian spring to late summer, but with no detection of methane.”

But don’t give up on microbial Martians just yet… “This important result will help direct our efforts to examine the possibility of life on Mars,” says NASA’s Michael Meyer. “It reduces the probability of current methane-producing Martian microbes, but this addresses only one type of microbial metabolism. As we know, there are many types of terrestrial microbes that don’t generate methane.”

Looking for extraterrestrial life? Next month’s Brilliant!Science festival can deliver it to you. Visit this page for more information.

Image: the Tunable Laser Spectrometer on-board Curiosity: NASA/JPL-Caltech

Has Voyager 1 finally left the Solar System?

An answer to this question has been proclaimed so many times in the last few years that it has almost lost its effect. Part of the confusion lies in how we define “solar system.” Is it the edge of planetary orbits or the end of the Sun’s influence…or is there yet another definition?

Launched in 1977, the craft has been hurtling through space at an incredible 38,000 miles per hour, sprinting nearly 1,000,000 miles per day. It passed the orbit of the farthest planet Neptune on August 25, 1989 (at the time, due to its highly elliptical orbit, the then-planet Pluto was closer to the Sun than Neptune). Its twin spacecraft, Voyager 2, actually flew close to the planet itself. In 1990, with their planetary missions accomplished, both Voyager missions were renamed the Voyager Interstellar Mission. This consists of three phases: detection of the termination shock (the edge of the Sun’s magnetic influence, where the solar wind slows); exploration of the heliopause (the interface between the solar wind and the interstellar wind); and exploration of interstellar space (the region where the interstellar wind dominates). In December 2004, Voyager crossed the termination shock. Roughly ten years later, the craft was expected to transverse the heliopause, which many consider the edge of the Solar System.

And on August 25, 2012, 35 years after its launch and 12 billion miles (125.3 AU) from the Sun, Voyager 1 officially crossed into interstellar space.

The determination that the event actually occurred, however, did not come until last week. What took so long?

The Sun ejects plasma material (called the “solar wind”) out into a bubble called the heliosphere. The plasma outside that sphere comes from stellar explosions millions of years ago and has since been dispersed throughout the galaxy. The interaction between the heliosphere and plasma is the boundary between the two.

Voyager was looking to detect that boundary between plasmas; however, it could not do this directly because the plasma detector on Voyager 1 malfunctioned in 1980, just a few years after launch. Instead, scientists measured the magnetic field of the Sun and of the interstellar wind. The change did not manifest as expected, so scientists could not draw a definite conclusion. Another set of instruments on board, two antennae, are able to measure plasma—but only if it is moving in waves. A solar eruption in March 2012 sent a shock wave that took 400 days to reach Voyager, but caused the plasma to react in a way that Voyager could detect. This signal finally enabled the confirmation of the craft’s passage into interstellar space.

Sadly, our connection with Voyager will eventually end as its power runs out (its current power output is about that of a refrigerator lightbulb—try detecting that from 11 billion miles away!) The craft is expected to lose all power and cease its communications with Earth by 2025. With no friction to slow it down, however, Voyager will continue to drift on, indefinitely. It remains well within the sphere of the Sun’s gravitational dominion, but will take about 30,000 years to pass through the Oort cloud, the cometary halo extending about a light year or so from the Sun and the farthest-known objects orbiting the Sun. So although the plucky spacecraft has entered interstellar space and left the Sun’s magnetic influence, the Voyager team says it will not yet leave the Solar System until it passes through the Oort Cloud. Beyond that, it will take another 70,000 years to travel the 4.3 light year distance between us and the next closest star, Alpha Centari.

But let’s not underestimate the significance of this event. A man-made object has left the confines of the tiny speck of our galactic home for the very first time and entered the space between stars. We have physically entered a space greater than any explored before and taken the first step in ever visiting other star systems. True, it is a mere 16 light hours, but substantially farther than the 1.3 light seconds to the Moon, which is the farthest that humans have gone.

Voyager leads the way in a whole new frontier of exploration.

Elise Ricard is the Senior Presenter at the Morrison Planetarium and holds a master’s degree in museum education.

While there is no officially acknowledged “man in the moon,” there is a LADEE (channel your inner Scot as you say it, “lad-ee”), or there will be soon. NASA’s upcoming Lunar Atmosphere and Dust Environment Explorer (LADEE) is slated for launch today! This mission will give us a chance to revisit the lunar surface in great detail—and possibly determine the cause of some strange observations made decades ago during the Apollo missions.

When taking coronal photographs in 1971, the Apollo 15 astronauts found what they described as “excessive brightness” on the lunar surface. One objective of the LADEE mission is to determine the nature of this glow, thought to be a loose lunar atmosphere. (If an atmosphere exists, it’s much, MUCH less dense than ours.) The glow could also be caused by electrostatically charged dust that hovers around the lunar surface.

In order to get to the Moon, LADEE will take off on a Minotaur V launch vehicle, made from a converted peacekeeper missile—the first launch of its kind. It’s based on the Minotaur IV system, which has been used successfully many times.

After launch, LADEE will spend 30 days making its way to the Moon and establishing a stable orbit 156 kilometers above the surface; it will spend the next 30 days aligning, checking out, and tuning up its scientific instruments. The 100-day-long science portion of the mission will then allow NASA researchers to observe the lunar environment carefully and put to rest the 38-year-old mystery.

The tools onboard consist of an Ultraviolet and Visible Light Spectrometer (UVS), which will analyze chemical compounds and determine their elemental makeup; the Neutral Mass Spectrometer (NMS), which will help determine just how much atmosphere the moon has; and finally, the Lunar Dust Experiment (LDEX).

LADEE will also establish a higher bandwidth, more robust connection than any prior lunar mission, using laser-based communication instead of the traditional low-power radio-based system enabling more information to be sent faster. That’s right! NASA is deploying experimental space lasers to communicate with LADEE. How sci fi is that?

LADEE represents a synthesis of both new and well-tested technologies and a great chance for us to better understand our nearest neighbor in space.

Josh Roberts is a program presenter and astronomer at the California Academy of Sciences. He also contributes content to Morrison Planetarium productions.

Image: NASA EDGE

Recently, the search for extrasolar planets (a.k.a. exoplanets) has centered around finding an Earth-like world, a place where life as we know it could exist. After all, wouldn’t it be exciting to discover extraterrestrials—or at least a new place humans could inhabit? Problematically, these small, potentially inhabitable planets are terribly challenging to detect. Twenty years of searching has yielded 941 (and counting) confirmed planets, but none very much like Earth… Although we are well on our way to finding such a “Goldilocks” world (not too hot, not too cold, but juuuust right), other, often larger exoplanets are proving easier to find and uniquely interesting.

A significant percentage of the exoplanets uncovered so far are “hot Jupiters”—colossal gas giant worlds that equal or surpass the mass of Jupiter and orbit very close to their parent stars, creating high surface temperatures as a result. One particularly interesting giant is HD 189733b, a massive world a mere 63 light years away. Though discovered in 2005, its proximity to our solar system makes it a good exoplanet to examine.

Some of the more interesting recent studies of this exoplanet leave behind the question of habitability to examine different planetary characteristics. In 2008, astrophysicists used polarimetry to detect and monitor the planet in visible light and determined an overall color of the world as it would appear to us. A second set of independent tests came back just this last month with the same result. The planet, as we would perceive it, is cobalt blue!

The discovery of another blue marble in the Milky Way is enticing. But this blue color is obviously not due to liquid oceans covering its surface. So where is the color coming from? It could be caused by a slow shower of molten glass. Observations have shown the likely presence of silicate particles in the lower atmosphere. This would scatter light in such a ways as to appear blue in the visible spectrum. Silicate is a component of glass which has lead some researchers to suspect the atmosphere might rain intensely heated bits of molten glass. Certainly not a storm you would want to be caught in!

Looking closer at the planet, all similarities to Earth continue to sizzle away. Orbiting 30 times closer to its star than Earth is to the Sun (which works out to about 13 times closer to its star than Mercury is from the Sun), this planet definitely qualifies as a HOT Jupiter: 1,200°F (650°C) on the night side to 1,700°F (930°C) on the day side with winds as fast as 6,000 miles per hour (nearly a thousand kilometers per hour). This is not a life-friendly place. In fact, Scott Wolk of the Center for Astrophysics estimates the atmosphere of the planet is boiling away at about 660,000 to 100 million tons of mass per second.

HD 189733b is a fantastic example of the surprises that continue to amaze us as we learn more about our universe. Hot Jupiters are not places we study in the hopes of finding life. Rather, we explore these fascinating places so different from our own world to learn about the diversity of planetary systems in our galaxy. They help us uncover more about the evolution of planets and allow us to probe the conditions that came together to form the immense diversity of worlds that we see. They provide clues and contrasts to our own planet, where the processes of life were able to take hold and evolve.

Could Earth have once been a hot Jupiter instead? Quite unlikely. Can HD 189733b ever be the next Earth? Not likely. But these bizarre and far-off worlds are certainly engaging in their own right.

Elise Ricard holds a master’s degree in museum education and is a presenter at Morrison Planetarium.

Images: X-ray: NASA/CXC/SAO/K. Poppenhaeger et al; Illustration: NASA/CXC/M. Weiss

Supervolcanoes here on Earth capture a lot of attention; from doomsday predictions to TV specials to planetarium shows, many folks seem concerned about these phenomena occurring at any moment from far beneath our feet.

But when searching for volcanoes, instead of down, maybe we should look up. We have found many unusual types of volcanoes in space.

A recent photo of Io, one of Jupiter’s moons, has just revealed a massive eruption on the surface of the large moon. The spread of the returning material covers about 30 square kilometers (11.5 square miles), making it one of the largest eruptions humans have ever witnessed and placing it within the top ten eruptions on Io.

Why is Io so active? The most likely explanation is the gravitational tug of war between the tidally locked moon and the massive planet Jupiter. This constant pulling and stretching is keeping the moon warm and fluid.

But why do explosions halfway across the Solar System away interest scientists? What we learn about these volcanic eruptions can help us understand volcanoes here on Earth a bit better and also give us a glimpse “under the hood” of Io.

And perhaps the coolest reason of all? Scientists studying the ice moon next to Io, Europa, have found magnesium salts on the surface of that moon that may have been spread there by Io throwing material into orbit around Jupiter! Some of that volcanic spray may be shared amongst the rest of the great moons of Jupiter as well. Evidence that these worlds have a diverse mix of chemicals is a big step toward determining the kind of primordial soup that could exist upon (or within) them, not to mention the kind of chemistry—or, perhaps, even evolution—that could be occurring there.

Josh Roberts is a program presenter and astronomer at the California Academy of Sciences. He also contributes content to Morrison Planetarium productions.

Image: NASA’s Galileo spacecraft

We tend to think of these scary objects as having voracious appetites, gobbling up everything that gets in their way. But in reality, most black holes surround themselves with discs of gas and dust that swirl around, heat up, and emit lots of radiation. All this activity makes it difficult to determine what’s going on near the black hole itself. Which includes figuring out the black hole’s diet.

If we want to understand something that’s invisible (such as a black hole), we usually have to find creative ways of detecting it. But in order to learn about the black hole at the center of our galaxy, astronomers study the behavior of its surroundings—specifically nearby stars.

They hit the jackpot once they discovered a pulsar near the galactic center. Not only do these rare stars act as precise cosmic clocks, but this one in particular emits an abnormally strong magnetic field (called a magnetar).

Pulsar PSR J1745-2900 was the first of its kind to be found near the galactic center, and at only 0.3 light years away from our black hole (a.k.a. Sagittarius A* or Sgr A*), it tells us a lot about black hole characteristics.

A research team with the Max Planck Institute for Radio Astronomy (MPIfR) was able to measure the pulsar’s magnetic field, which revealed how magnetic fields affect black hole behavior.

“In order to understand the properties of Sgr A*, we need to comprehend the accretion of gas into the black hole,” says Michael Kramer, director at MPIfR. Although black holes have infamously strong gravity, material doesn’t typically fall directly into a black hole; instead, the material forms an accretion disc before slowly flowing toward the black hole at the center.

“However, up to now,” according to Kramer, “the magnetization of the gas, which is a crucial parameter determining the structure of the accretion flow, remains unknown. Our study changes that by using the discovered pulsar to probe the strength of the magnetic field at the start of this accretion flow of gas into the central object.”

Knowledge of pulsars’ consistent frequencies illustrates the effect of the black hole on the pulsar. Radio waves usually polarized along a plane are now rotating in a corkscrew motion, similar to the radiation emitted from black holes themselves.

“The rotation is way higher than anything seen in the Galaxy with the exception of Sagittarius A*,” says Ralph Eatough of MPIfR who measures the black hole’s radio waves and outward streaming matter.

The paper, published last week in Nature, concludes that the twisted magnetic fields might slow black holes’ diet, putting the brakes on infalling gas. Sgr A* is “not feeding to its full potential,” says Eatough.

Alyssa Keimach is an astronomy and astrophysics student at the University of Michigan and interns for the Morrison Planetarium.

Image: NASA

Seashells, tornados and spiral galaxies all feature similar spiral shapes. Patterns repeat themselves in nature over and over again.

Gravity produces more abstract patterns: in much the same way that moving boats produce waves on water, moving stars can create gravitational waves in the fabric of space-time. Both types of waves lose energy as they move farther away from their source. Unfortunately, gravitational waves are very hard to measure by the time they reach Earth, and to this point, astronomers have not managed to detect gravitational waves from anywhere in the Universe.

But that doesn’t mean astronomers have given up. The quest to detect these waves has inspired scientists to figure out all kinds of ways gravitational waves might be created…

Discovered three short years ago, “monster” stars have masses between 200 and 300 times that of our sun—vastly larger than any other stars. Astronomers hoped that collisions between their supermassive remnants would produce measurable gravitational waves. At the 10th Edoardo Amaldi Conference on Gravitational Waves, Dr. Krzysztof Belczyński of the Astronomical Observatory of the Faculty of Physics at the University of Warsaw revealed his most recent findings.

Stars frequently form binary systems (two orbit around each other). Components of such systems collide once one object’s atmosphere takes over the other in a “common-envelope event.” The end result produces gamma-ray bursts accompanied by gravitational waves.

It would seem that a monster binary system would produce monster gravitational waves that even our current detectors could measure. Unfortunately, it seems that these monster stars will never get close enough to collide in the first place.

“In a supermassive binary star system, the situation is different,” says Dr. Belczyński. “We know that the components of such a system must be formed at a relatively large distance from each other. We also know that supermassive stars do not expand, so there cannot be a common envelope phase. This means that there is no physical mechanism that would effectively cause the orbit to tighten!”

“We stand practically no chance of detecting the gravitational waves from such a collision in the heavens. Unless…” Dr. Daniel Holz of the University of Chicago trails off in mid-sentence. We might detect such a collision if our current model of binary systems is wrong, which would demand a revision in our understanding of how the Universe works.

Thus the search continues for possible sources of gravitational waves—particularly of sufficient strength for us to detect. And preferably without the need to turn physics on its head.

Image: NASA