Posted on by Matt Williams

New Study Claims There are Four Exoplanets Around Nearest Sun-Like Star!

Artist's impression of a yellowish star being orbited by an extra-solar planet. Credit: ESO/L. Calçada

It has been an exciting time for the field of exoplanet studies lately! Last summer, researchers from the European Southern Observatory (ESO) announced the discovery of an Earth-like planet (Proxima b) located in the star system that is the nearest to our own. And just six months ago, an international team of astronomers announced the discovery of seven rocky planets orbiting the nearby star TRAPPIST-1.

But in what could be the most encouraging discovery for those hoping to find a habitable planet beyond Earth, an an international team of astronomers just announced the discovery of four exoplanet candidates in the tau Ceti system. Aside from being close to the Solar System – just 12 light-years away – this find is also encouraging because the planet candidates orbit a star very much like our own!

The study that details these findings – “Color difference makes a difference: four planet candidates around tau Ceti” – recently appeared online and has been accepted for publication in the Astrophysical Journal. Led by researchers from the Center for Astrophysics Research (CAR) at the University of Hertfordshire, the team analyzed tau Ceti using a noise-eliminating model to determine the presence of four Earth-like planets.

This illustration compares the four planets detected around the nearby star tau Ceti (top) and the inner planets of our solar system (bottom). Credit: Fabo Feng/CAR/Univ. of Hertfordshire

This discovery was made possible thanks to ongoing improvements in instrumentation, observation and data-sharing, which are allowing for surveys of ever-increasing sensitivity. As Steven Vogt, a professor of astronomy and astrophysics at UC Santa Cruz and a co-author on the paper, said in a UCSC press release:

“We are now finally crossing a threshold where, through very sophisticated modeling of large combined data sets from multiple independent observers, we can disentangle the noise due to stellar surface activity from the very tiny signals generated by the gravitational tugs from Earth-sized orbiting planets.”

This is the latest in a long-line of surveys of tau Ceti, which has been of interest to astronomers for decades. By 1988, several radial velocity measurements were conducted of the star system that ruled out the possibility of massive planets at Jupiter-like distances. In 2012, astronomers from UC Santa Barabara presented a study that indicated that tau Ceti might be orbited by five exoplanets, two of which were within the star’s habitable zone.

The team behind that study included several members who produced this latest study. At the time, lead author Mikko Tuomi (University of Hertfordshire, a co-author on the most recent one) was leading an effort to develop better data analysis techniques, and used this star as a benchmark case. As Tuomi explained, theses efforts allowed them to rule out two of the signals that has previously been identified as planets:

“We came up with an ingenious way of telling the difference between signals caused by planets and those caused by star’s activity. We realized that we could see how star’s activity differed at different wavelengths and use that information to separate this activity from signals of planets.”

Artist’s impression of the Tau Ceti system, based on data retrieved in 2012. Credit: J. Pinfield/Univ. of Hertfordshire

For the sake of this latest study – which was led by Fabo Feng, a member of the CAR – the team relied on data provided by the High Accuracy Radial velocity Planet Searcher (HARPS) spectrograph at the ESO’s La Silla Observatory in Chile, and the High Resolution Echelle Spectrometer (HIRES) instrument at the W. M. Keck Observatory in Mauna Kea, Hawaii.

From this, they were able to create a model that removed “wavelength dependent noise” from radial velocity measurements. After applying this model to surveys made of tau Ceti, they were able to obtain measurements that were sensitive enough to detect variations in the star’s movement as small as 30 cm per second. In the end, they concluded that tau Ceti has a system of no more than four exoplanets.

As Tuomi indicated, after several surveys and attempts to eliminate extraneous noise, astronomers may finally have a clear picture of how many planets tau Ceti has, and of what type. “[N]o matter how we look at the star, there seem to be at least four rocky planets orbiting it,” he said. “We are slowly learning to tell the difference between wobbles caused by planets and those caused by stellar active surface. This enabled us to essentially verify the existence of the two outer, potentially habitable planets in the system.”

They further estimate from their refined measurements that these planets have masses ranging from four Earth-masses (aka. “super-Earths”) to as low as 1.7 Earth masses, making them among the smallest planets ever detected around a nearby sun-like star. But most exciting of all is the fact that that two of these planets (tau Ceti e and f) are located within the star’s habitable zone.

Recent studies have shown that rocky planets orbiting red dwarf stars will be tidally-locked and subject to intense radiation, reducing their chances of being habitable. Credit: M. Weiss/CfA

The reason for this is because tau Ceti is a G-type (yellow dwarf) star, which makes it similar to our own Sun – about 0.78 times as massive and half as bright. In contrast, many recently discovered exoplanets – such as Proxima b and the seven planets of TRAPPIST-1 – all orbit M-type (red dwarf) stars. Compared to our Sun, these stars are variable and unstable, increasing their chances of stripping the atmospheres of their respective planets.

In addition, since red dwarfs are much dimmer than our Sun, a rocky planet would have to orbit very closely to them  in order to be within their habitable zones. At this kind of distance, the planet would likely be tidally-locked, meaning that one side would constantly be facing towards the sun. This too makes the odds of life emerging on any such planet pretty slim.

Because of this, astronomers have been looking forward to finding more exoplanets around stars that are closer in size, mass and luminosity to our own. But before anyone gets too excited, its important to note these worlds are Super-Earths – with up to four times the mass of Earth. This means that (depending on their density as well) any life that might emerge on these planets would be subject to significantly increased gravity.

In addition, a massive debris disc surrounds the star, which means that these outermost planets are probably subjected to intensive bombardment by asteroids and comets. This not doesn’t exactly bode well for potential life on these planets! Still, this study is very encouraging, and for a number of reasons. Beyond finding strong evidence of exoplanets around a Sun-like star, the measurements that led to their detection are the most sensitive to date.

Artist’s impression of how an infant earth might look. Credit: ESO.

At the rate that their methods are improving, researchers should be getting to the 10-centimeter-per-second limit in no time at all. This is the level of sensitively required for detecting Earth analogs – aka. the brass ring for exoplanet-hunters. As Feng indicated:

“Our detection of such weak wobbles is a milestone in the search for Earth analogs and the understanding of the Earth’s habitability through comparison with these analogs. We have introduced new methods to remove the noise in the data in order to reveal the weak planetary signals.”

Think of it! In no time at all, exoplanet-hunters could be finding a plethora of planets that are not only very close in size and mass to Earth, but also orbiting within their stars habitable zones. At that point, scientists are sure to dispense with decidedly vague terms like “potentially habitable” and “Earth-like” and begin using terms like “Earth-analog” confidently. No more ambiguity, just the firm conviction that Earth is not unique!

With an estimated 100 billion planets in our galaxy alone, we’re sure to find several Earths out here. One can only hope they have given rise to complex life like our own, and that they are in the mood to chat!

Further Reading: UCSC, arXiv

Posted on by Matt Williams

What are Gas Giants?

The outer planets of our Solar System at approximately relative sizes. From left, Jupiter, Saturn, Uranus and Neptune. Credit: Lunar and Planetary Institute

Between the planets of the inner and outer Solar System, there are some stark differences. The planets that resides closer to the Sun are terrestrial (i.e. rocky) in nature, meaning that they are composed of silicate minerals and metals. Beyond the Asteroid Belt, however, the planets are predominantly composed of gases, and are much larger than their terrestrial peers.

This is why astronomers use the term “gas giants” when referring to the planets of the outer Solar System. The more we’ve come to know about these four planets, the more we’ve come to understand that no two gas giants are exactly alike. In addition, ongoing studies of planets beyond our Solar System (aka. “extra-solar planets“) has shown that there are many types of gas giants that do not conform to Solar examples. So what exactly is a “gas giant”?

Definition and Classification:

By definition, a gas giant is a planet that is primarily composed of hydrogen and helium. The name was originally coined in 1952 by James Blish, a science fiction writer who used the term to refer to all giant planets. In truth, the term is something of a misnomer, since these elements largely take a liquid and solid form within a gas giant, as a result of the extreme pressure conditions that exist within the interior.

The four gas giants of the Solar System (from right to left): Jupiter, Saturn, Uranus and Neptune. Credit: NASA/JPL

What’s more, gas giants are also thought to have large concentrations of metal and silicate material in their cores. Nevertheless, the term has remained in popular usage for decades and refers to all planets  – be they Solar or extra-solar in nature – that are composed mainly of gases. It is also in keeping with the practice of planetary scientists, who use a shorthand – i.e. “rock”, “gas”, and “ice” – to classify planets based on the most common element within them.

Hence the difference between Jupiter and Saturn on the one and, and Uranus and Neptune on the other. Due to the high concentrations of volatiles (such as water, methane and ammonia) within the latter two – which planetary scientists classify as “ices” – these two giant planets are often called “ice giants”. But since they are composed mainly of hydrogen and helium, they are still considered gas giants alongside Jupiter and Saturn.

Classification:

Today, Gas giants are divided into five classes, based on the classification scheme proposed by David Sudarki (et al.) in a 2000 study. Titled “Albedo and Reflection Spectra of Extrasolar Giant Planets“, Sudarsky and his colleagues designated five different types of gas giant based on their appearances and albedo, and how this is affected by their respective distances from their star.

Class I: Ammonia Clouds – this class applies to gas giants whose appearances are dominated by ammonia clouds, and which are found in the outer regions of a planetary system. In other words, it applies only to planets that are beyond the “Frost Line”, the distance in a solar nebula from the central protostar where volatile compounds – i.e. water, ammonia, methane, carbon dioxide, carbon monoxide – condense into solid ice grains.

These cutaways illustrate interior models of the giant planets. Jupiter is shown with a rocky core overlaid by a deep layer of metallic hydrogen. Credit: NASA/JPL

Class II: Water Clouds – this applies to planets that have average temperatures typically below 250 K (-23 °C; -9 °F), and are therefore too warm to form ammonia clouds. Instead, these gas giants have clouds that are formed from condensed water vapor. Since water is more reflective than ammonia, Class II gas giants have higher albedos.

Class III: Cloudless – this class applies to gas giants that are generally warmer – 350 K (80 °C; 170 °F) to 800 K ( 530 °C; 980 °F) – and do not form cloud cover because they lack the necessary chemicals. These planets have low albedos since they do not reflect as much light into space. These bodies would also appear like clear blue globes because of the way methane in their atmospheres absorbs light (like Uranus and Neptune).

Class IV: Alkali Metals – this class of planets experience temperatures in excess of 900 K (627 °C; 1160 °F), at which point Carbon Monoxide becomes the dominant carbon-carrying molecule in their atmospheres (rather than methane). The abundance of alkali metals also increases substantially, and cloud decks of silicates and metals form deep in their atmospheres. Planets belonging to Class IV and V are referred to as “Hot Jupiters”.

Class V: Silicate Clouds – this applies to the hottest of gas giants, with temperatures above 1400 K (1100 °C; 2100 °F), or cooler planets with lower gravity than Jupiter. For these gas giants, the silicate and iron cloud decks are believed to be high up in the atmosphere. In the case of the former, such gas giants are likely to glow red from thermal radiation and reflected light.

Artist’s concept of “hot Jupiter” exoplanet, a gas giant that orbits very close to its star. Credit: NASA/JPL-Caltech)

Exoplanets:

The study of exoplanets has also revealed a wealth of other types of gas giants that are more massive than the Solar counterparts (aka. Super-Jupiters) as well as many that are comparable in size. Other discoveries have been a fraction of the size of their solar counterparts, while some have been so massive that they are just shy of becoming a star. However, given their distance from Earth, their spectra and albedo have cannot always be accurately measured.

As such, exoplanet-hunters tend to designate extra-solar gas giants based on their apparent sizes and distances from their stars. In the case of the former, they are often referred to as “Super-Jupiters”, Jupiter-sized, and Neptune-sized. To date, these types of exoplanet account for the majority of discoveries made by Kepler and other missions, since their larger sizes and greater distances from their stars makes them the easiest to detect.

In terms of their respective distances from their sun, exoplanet-hunters divide extra-solar gas giants into two categories: “cold gas giants” and “hot Jupiters”. Typically, cold hydrogen-rich gas giants are more massive than Jupiter but less than about 1.6 Jupiter masses, and will only be slightly larger in volume than Jupiter. For masses above this, gravity will cause the planets to shrink.

Exoplanet surveys have also turned up a class of planet known as “gas dwarfs”, which applies to hydrogen planets that are not as large as the gas giants of the Solar System. These stars have been observed to orbit close to their respective stars, causing them to lose atmospheric mass faster than planets that orbit at greater distances.

For gas giants that occupy the mass range between 13 to 75-80 Jupiter masses, the term “brown dwarf” is used. This designation is reserved for the largest of planetary/substellar objects; in other words, objects that are incredibly large, but not quite massive enough to undergo nuclear fusion in their core and become a star. Below this range are sub-brown dwarfs, while anything above are known as the lightest red dwarf (M9 V) stars.

An artist’s conception of a T-type brown dwarf. Credit: Tyrogthekreeper/Wikimedia Commons

Like all things astronomical in nature, gas giants are diverse, complex, and immensely fascinating. Between missions that seek to examine the gas giants of our Solar System directly to increasingly sophisticated surveys of distant planets, our knowledge of these mysterious objects continues to grow. And with that, so is our understanding of how star systems form and evolve.

We have written many interesting articles about gas giants here at Universe Today. Here’s The Planet Jupiter, The Planet Saturn, The Planet Uranus, The Planet Neptune, What are the Jovian Planets?, What are the Outer Planets of the Solar System?, What’s Inside a Gas Giant?, and Which Planets Have Rings?

For more information, check out NASA’s Solar System Exploration.

Astronomy Cast also has some great episodes on the subject. Here’s Episode 56: Jupiter to get you started!

Sources:

Posted on by Matt Williams

New Horizons’ Next Flyby Target Just Got Weirder!

Artist's impression of NASA's New Horizons spacecraft encountering a Pluto-like object in the distant Kuiper Belt. Credits: NASA/JHUAPL/SwRI/Alex Parker

Since it made its historic flyby of Pluto in July of 2015, the New Horizons mission has been venturing farther into the outer Solar System. With the spacecraft still healthy and its system in working order, the mission was extended to include the exploration of additional Kuiper Belt Objects (KBOs). The first target for this part of its mission is the KBO known as 2014 MU69, which New Horizons is currently making its way towards.

In the past, NASA believed this object was a spherical chunk of ice and rock measuring 18–41 km (10–30 mi) in diameter. However, a more recent occultation observation has led the New Horizon‘s team to conclude that MU69 may actually be a large object with a chunk taken out of it (an “extreme prolate spheroid”) or two objects orbiting very closely together or touching – aka. a close or contact binary.

In 2015, MU69 was identified as one of two potential destinations for New Horizons and was recommended to NASA by the mission science team. It was selected because of the immense opportunities for research it presented. As Alan Stern, the Principle Investigator (PI) for the New Horizons mission at the Southwest Research Institute (SwRI), indicated at the time:

“2014 MU69 is a great choice because it is just the kind of ancient KBO, formed where it orbits now, that the Decadal Survey desired us to fly by. Moreover, this KBO costs less fuel to reach [than other candidate targets], leaving more fuel for the flyby, for ancillary science, and greater fuel reserves to protect against the unforeseen.”

Artist’s concept of a binary object, which new data suggests 2014 MU69 (the next flyby target for NASA’s New Horizons mission) could be. Credits: NASA/JHUAPL/SwRI/Alex Parker

The most recent observation of the KBO took place on July 17th, 2017, when the object passed in front of a star. This provided the New Horizon’s team with an opportunity to measure the resulting dip in the star’s luminosity – aka. an occultation – using a series of telescopes that they had deployed to a remote part of Patagonia, Argentina. These sorts of observations are performed regularly in order to obtain estimates of an asteroid’s size and position.

In the case of MU69’s occulation, the New Horizons team was able to obtain vital data that will help the mission planners to plot the trajectory of their flyby. In addition, the data revealed things about MU69’s size, shape, orbit, and the environment that surrounds it. It was because of this that the team began to question earlier estimates on the object’s size and shape.

Based on their new observations, they are confident that the object is no more than 30 km (20 mi) long, if it is an extreme prolate spheroid.  If, however, it is a binary, the two objects that compose it are believed to measure about 15-20 km (9-12 mi) in diameter each. Alan Stern expanded on these new findings in a recent NASA press statement, saying:

“This new finding is simply spectacular. The shape of MU69 is truly provocative, and could mean another first for New Horizons going to a binary object in the Kuiper Belt. I could not be happier with the occultation results, which promise a scientific bonanza for the flyby.”

Artist’s concept of Kuiper Belt object 2014 MU69 as a single body (above) with a large chunk taken out of it. Credits: NASA/JHUAPL/SwRI/Alex Parker

The recent stellar occulation was the third of three observations conducted for the New Horizons mission. To prepare for the event, the New Horizons team traveled to Argentina and South Africa on June 3rd. On July 10th, a week before the occultation, NASA’s airborne Stratospheric Observatory for Infrared Astronomy (SOFIA) provided support by studying the space around MU69.

Using its 2.5 m (100-inch) telescope, SOFIA was looking for debris that might present a hazard to New Horizons spacecraft as it makes its flyby less than 17 months from now. Last, but certainly not least, the team also relied on data provided by NASA’s Hubble Space Telescope and the ESA’s Gaia satellite to calculate and pinpoint where MU69 would cast its shadow on Earth’s surface.

Thanks to their assistance, the New Horizons team knew exactly where the occultation shadow would be and set up their “fence line” of small, mobile telescopes accordingly. Marc Buie – the New Horizons co-investigator – was responsible for leading the observation campaign. As he explained, the data it yielded will be of great help in the planning the flyby, but also indicated that their could be some surprises in the future:

“These exciting and puzzling results have already been key for our mission planning,” he said, “but also add to the mysteries surrounding this target leading into the New Horizons encounter with MU69, now less than 17 months away.”

The flyby with MU69 is scheduled to take place on Jan. 1st, 2019, and will be the most distant flyby in the history of space exploration. In addition to being 1.6 billion km (1 billion mi) from Pluto, the New Horizons spacecraft will be 6.5 billion km (4 billion mi) from Earth! What’s more, the first-ever study of a KBO is expected to yield some fantastic scientific data, and tell us much about the formation and evolution of our Solar System.

 

Further Reading: NASA

Posted on by Nancy Atkinson

Gorgeous Images of the August 2017 Partial Lunar Eclipse

The partial lunar eclipse on August 7, 2017 as seen from Bucharest, Romania. Credit and copyright: Loredana Jucan.

Just to get you in the mood for the upcoming total solar eclipse — now less than two weeks away — our Solar System put on a little eclipse display of the lunar kind on August 7. The full Moon passed through part of the Earth’s umbral shadow, and the timing made this partial lunar eclipse visible in parts of Europe and Africa.

Thanks to our friends around the world who posted in Universe Today’s Flickr page, we’ve got images to share! Enjoy the views! Click on all the images to see larger versions of them on Flickr. The lead image link is here.

And for those of you in the path of the August 21 solar eclipse, please feel free to share your images on our Flickr page, and we may feature them in an upcoming article.

A composite of images take during the August 2017 lunar eclipse, as see from Kuala Lumpur. Credit and copyright: Shahrin Ahmad.
Partial lunar eclipse seen from Lausanne’s lakeshore in Switzerland … The Moon had just moved up from behind the Tour d’Aï Peaks. Credit and copyright: Hicham Dennaoui.
Partial Eclipse of Moon over the Church of Our Lady of the Bell in Casarano, Sicily, Italy. Single photo taken with a Konus 80/400 telescope and Canon 700d camera. Credit and copyright: Gianluca Belgrado.

Eclipsed full moon over the eastern horizon as seen from Treppendorf, Brandenburg, Germany. Credit and copyright: Andreas Schnabel.
Partial lunar eclipse of August 7th 2017, as seen from Bavaria, Germany at around 19:17 UTC. Shot with an EOS 550D mounted to a Meade ETX 70 Telescope. Exposure was 1/125 seconds with ISO 100. Credit and copyright:
Stephan Haverland.
The partial lunar eclipse as see from Czolpino, Pomerania, Poland. Credit and copyright:
Pawel Warchal.
A view of the partial lunar eclipse on August 7, 2017 as seen from Malta in the Mediterranean Sea. Credit and copyright: Leonard Ellul-Mercer.

Here is a video of additional images from Leonard Mercer:

You can watch a reply of a live webcast from the Virtual Telescope Project of the partial lunar eclipse seen from Rome:

Posted on by Matt Williams

Experiment Detects Mysterious Neutrino-Nucleus Scattering For the First Time

The Spallation Neutron Source, located at the Oak Ridge National Laboratory. Credit: neutrons.ornl.gov

Neutrinos are one of the fundamental particles that make up the Universe. Compared to other types of particles, they have very little mass, no charge, and only interact with others via the weak nuclear force and gravity. As such, finding evidence of their interactions is extremely difficult, requiring massive instruments located deep underground to shield them from any interference.

However, using the Spallation Neutron Source (SNS), a research facility located at the Oak Ridge National Laboratory (ORNL) – an international team of researchers recently made a historic discovery about neutrinos using an entirely different method. As part of the COHERENT experiment, these results confirm a prediction made 43 years ago and offers new possibilities for neutrino research.

Continue reading “Experiment Detects Mysterious Neutrino-Nucleus Scattering For the First Time”
Posted on by Tammy Plotner

Messier 53 – the NGC 5024 Globular Cluster

Messier 53, as imaged by the Hubble Space Telescope. Credit: ESA/Hubble & NASA

Welcome back to Messier Monday! In our ongoing tribute to the great Tammy Plotner, we take a look at globular cluster known as Messier 53!

During the 18th century, famed French astronomer Charles Messier noted the presence of several “nebulous objects” in the night sky. Having originally mistaken them for comets, he began compiling a list of these objects so others would not make the same mistake he did. In time, this list (known as the Messier Catalog) would come to include 100 of the most fabulous objects in the night sky.

One of these objects is Messier 53, a globular cluster located in the northern Coma Berenices constellation. Located about 58,000 light years from the Solar System, it is almost equidistant from Galactic Center (about 60,000 light years). As Messier Objects go, it is relatively easy to find since it lies in the same area of the sky as Arcturus, the fourth brightest star in the night sky.

Description:

Heading towards us at a speed of 112 kilometers per second, globular cluster M53 is one of the furthest distant globular clusters in our Milky Way halo and lay almost equally distant between our solar system and the galactic center. This 220 light year diameter ball of stars in tightly compacted towards its core – where low metal is the name of the game and RR Lyra type variable stars once ruled. But recent studies have found that there are some new kids on the block. The blue stragglers…

Messier 53, as imaged by the Hubble Space Telescope. Credit: ESA/Hubble & NASA

According to G. Beccari (et al) the population of these definitely appears to violate standard theories of stellar evolution. And there not just a few blues… There’s a whole host of them. As Beccari noted in a 2008 study:

“We used a proper combination of high-resolution and wide-field multiwavelength observations collected at three different telescopes (HST, LBT, and CFHT) to probe the blue straggler star (BSS) population in the globular cluster M53. Almost 200 BSSs have been identified over the entire cluster extension. We have also used this database to construct the radial star density profile of the cluster; this is the most extended and accurate radial profile ever published for this cluster, including detailed star counts in the very inner region. A deviation from the model is noted in the most external region of the cluster. This feature needs to be further investigated in order to address the possible presence of a tidal tail in this cluster.”

Is this possible? Then take a closer look into this research. One where a millisecond pulsar was discovered inside. As S.R. Kulkarni (et al) indicated in a 1991 study:

“Millisecond pulsars are conventionally assumed to be spun up through the action of binary companions, although some subsequently lose their companions and appear as isolated pulsars. Such objects should therefore be more numerous in dense stellar systems. We report here the surprising discovery of two pulsars in low-density globular clusters: one is a single 10-ms pulsar (1639+36) in M13 (NGC 6205), the other a 33-ms pulsar (1310+18) in a 256-d binary in M53 (NGC 5024). Their ages, inferred from their luminosities and constraints on their period derivatives, seem to be 10 9 years, significantly greater than previously reported ages ( ! 10 8 years) of cluster pulsars. The implied birth rate is inconsistent with the conventional two-body tidal capture model, suggesting that an alternative mechanism such as tidal capture between primordial binaries and a reservoir of (hundreds of) primordial neutron stars may dominate the production of tidal binaries in such clusters. The period derivative of PSR1639+36 is surprisingly small, and may be corrupted by acceleration due to the mean gravitational potential of the cluster.”

The Messier 53 globular star cluster. Credit: Ole Nielsen

History of Observation:

This globular cluster was first discovered on February 3, 1775 by Johann Elert Bode, but independently recovered on February 26, 1777 by Charles Messier who writes:

“Nebula without stars discovered below & near Coma Berenices, a little distant from the star 42 in that constellation, according to Flamsteed. This nebula is round and conspicuous. The Comet of 1779 was compared directly with this nebula, & M. Messier has reported it on the chart of that comet, which will be included in the volume of the Academy for 1779. Observed again April 13, 1781: It resembles the nebula which is below Lepus [M79].”

Sir William Herschel would revisit M53, but he did not publish his findings when studying Messier objects. Very seldom did Herschel wax poetic in his writings, but of this particular object he said: “A cluster of very close stars; one of the most beautiful objects I remember to have seen in the heavens. The cluster appears under the form of a solid ball, consisting of small stars, quite compressed into one blaze of light, with a great number of loose ones surrounding it, and distinctly visible in the general mass.”

He would return again in later years to include in his notes: “From what has been said it is obvious that here the exertion of a clustering power has brought the accumulation and artificial construction of these wonderful celestial objects to the highest degree of mysterious perfection.”

The Messier 53 globular cluster. Credit: NASA/ESA/Hubble

Although it did not touch Sir John Herschel quite so much, M53 also engaged Admiral Smyth who wrote:

“A globular cluster, between Berenice’s tresses and the Virgin’s left hand, with a coarse pair of telescopic stars in the sf [south following, SE] quadrant, and a single one in the sp [south preceding, SW]. This is a brilliant mass of minute stars, from the 11th to the 15th magnitude, and from thence to gleams of star-dust, with stragglers to the np [north preceding, NW], and pretty diffused edges. From the blaze at the centre, it is evidently a highly compressed ball of stars, whose law of aggregation into so dense and compact a mass, is utterly hidden from our imperfect senses. It was enrolled by Messier in 1774 as No. 53, and resolved into stars by Sir W. Herschel. The contemplation of so beautiful an object, cannot but set imagination to work, though the mind may be soon lost in astonishment at the stellar dispositions of the great Creator and Maintainer. Thus, in reasoning by analogy, these compressed globes of stars confound conjecture as to the models in which the mutual attractions are prevented from causing the universal destruction of their system. Sir John Herschel thinks, that no pressure can be propagated through a cluster of discrete stars; whence it would follow, that the permanence of its form must be maintained in a way totally different from that which our reasoning suggest. Before quitting this interesting ball of innumerable worlds, I may mention that it was examined by Sir John Herschel, with Mr. Baily, in the 20-foot reflector; and that powerful instrument showed the cluster with curved appendages of stars, like the short claws of a crab running out from the main body. A line through Delta and Epsilon Virginis, northward, meeting another drawn from Arcturus to Eta Bootis, unite upon this wonderful assemblage; or it is also easily found by its being about 1 deg northeast of 42 Comae Berenices, the alignment of which is already given.”

Locating Messier 53:

M53 can be easily found just about a degree northeast of 42 Alpha Comae Berenices, a visual binary star. To located Alpha, draw a mental line from Arcturus via Eta Bootis where you’ll see it about a fist width west. Alternately you can starhop from Gamma Viginis to Delta and on to Epsilon where you can locate M53 approximately 4 fingerwidths to the north/northeast.

To see this small globular cluster in binoculars will require dark skies and it will appear very small, like a large, out of focus star. In small telescopes it will appear almost cometary – and thus why Messier cataloged these objects! However, with telescopes approaching the 6″ range, resolution will begin and larger telescopes will shatter this gorgeous globular cluster. Requires dark skies.

The location of Messier 53 in the northern Coma Berenices constellation. Credit: IAU and Sky & Telescope magazine (Roger Sinnott & Rick Fienberg)

A ball of worlds… What a unique description! May you enjoy your observations as well!

And here are the quick facts on this Messier Object to help you get started!

Object Name: Messier 53
Alternative Designations: M53, NGC 5024
Object Type: Class V Globular Cluster
Constellation: Coma Berenices
Right Ascension: 13 : 12.9 (h:m)
Declination: +18 : 10 (deg:m)
Distance: 58.0 (kly)
Visual Brightness: 7.6 (mag)
Apparent Dimension: 13.0 (arc min)

We have written many interesting articles about Messier Objects here at Universe Today. Here’s Tammy Plotner’s Introduction to the Messier Objects, , M1 – The Crab Nebula, M8 – The Lagoon Nebula, and David Dickison’s articles on the 2013 and 2014 Messier Marathons.

Be to sure to check out our complete Messier Catalog. And for more information, check out the SEDS Messier Database.

Sources:

Posted on by Ken Kremer

Musk Says Maiden Falcon Heavy to Launch in November, Acknowledges High Risk and Releases New Animation

SpaceX Falcon Heavy rocket poised for launch from the Kennedy Space Center in Florida in this artists concept. Credit: SpaceX

SpaceX Falcon Heavy rocket poised for launch from the Kennedy Space Center in Florida in this artists concept. Credit: SpaceX

Before the year is out, the long awaited debut launch of the triple barreled Falcon Heavy rocket may at last be in sight says SpaceX CEO and founder Elon Musk, as he forthrightly acknowledges it comes with high risk and released a stunning launch and landing animation earlier today, Aug. 4.

After years of painstaking development and delays, the inaugural blastoff of the SpaceX Falcon Heavy is currently slated for November 2017 from NASA’s Kennedy Space Center in Florida, according to Musk.

“Falcon Heavy maiden launch this November,” SpaceX CEO and billionaire founder Elon Musk tweeted last week.

“Lot that can go wrong in the November launch …,” Musk said today on Instagram, downplaying the chances of complete success.

And to whet the appetites of space enthusiasts worldwide, just today Musk also published a one minute long draft animation illustrating the Falcon Heavy triple booster launch and how the individual landings of the trio of first stage booster cores will take place – nearly simultaneously.

https://www.instagram.com/p/BXXiVWFgphb/

Video Caption: SpaceX Falcon Heavy launch from KSC pad 39A pad and first stage booster landings. Credit: SpaceX

“Side booster rockets return to Cape Canaveral,” explains Musk on twitter. “Center lands on droneship.”

The two side boosters will be recycled from prior Falcon 9 launches and make precision guided propulsive, upright ground soft landings back at Cape Canaveral Air Force Station, Florida. Each booster is outfitted with a quartet of grid fins and landing legs. The center core is newly built and heavily modified.

“Sides run high thrust, center is lower thrust until sides separate & fly back. Center then throttles up, keeps burning & lands on droneship. If we’re lucky!” Musk elaborated.

The center booster will touch down on an ocean going droneship prepositioned in the Atlantic Ocean some 400 miles (600 km) off of Florida’s east coast.

To date SpaceX first stages from KSC launches have touched down either on land at Landing Zone-1 (LZ-1) at the Cape or at sea on the “Of Course I Still Love You” droneship barge (OCISLY).

The launch of the extremely complicated Falcon Heavy booster with 27 first stage Merlin 1D engines also comes associated with a huge risk – and he hopes that it at least rises far enough off the ground to minimize the chances of damage to the historic pad 39A at the Kennedy Space Center.

“There’s a lot of risk associated with Falcon Heavy, a real good chance that that vehicle does not make it to orbit,” Musk said recently while speaking at the International Space Station Research and Development Conference in Washington, D.C. on July 19.

“I want to make sure to set expectations accordingly. I hope it makes it far enough beyond the pad so that it does not cause pad damage. I would consider even that a win, to be honest.”

Musk originally proposed the Falcon Heavy in 2011 and targeted a maiden mission in 2013.

Whenever it does launch, the Falcon Heavy will become the world’s most powerful rocket.

“I think Falcon Heavy is going to be a great vehicle,” Musk stated. “There’s just so much that’s really impossible to test on the ground, and we’ll do our best.

“Falcon Heavy requires the simultaneous ignition of 27 orbit-class engines. There’s a lot that can go wrong there.”

Designing and building Falcon Heavy has proven to be far more difficult than Musk ever imagined, and the center booster had to be significantly redesigned.

“It actually ended up being way harder to do Falcon Heavy than we thought,” Musk explained.

“At first it sounds real easy! You just stick two first stages on as strap-on boosters. How hard can that be?” But then everything changes. All the loads change, aerodynamics totally change. You’ve tripled the vibration and acoustics. You sort of break the qualification levels on so much of the hardware.”

“The amount of load you’re putting through that center core is crazy because you’ve got two super-powerful boosters also shoving that center core. So we had to redesign the whole center core airframe,” Musk added. “It’s not like the Falcon 9 – because it’s got to take so much load. Then you’ve got separation systems.”

Due to the high risk, there will be no payload from a paying customer housed inside the nose cone atop the center core. Only a dummy payload will be installed on the maiden mission.

However future Falcon Heavy missions have been manifested with commercial and science payloads.

Musk also hopes to launch a pair of paying private astronauts on a trip around the Moon and back as soon as 2018 while journeying inside a Crew Dragon spacecraft with the Falcon Heavy – similar to what his company is developing for NASA for commercial ferry missions to low Earth orbit (LEO) and the International Space Station (ISS).

Falcon Heavy will blast off with about twice the thrust of the Delta IV Heavy, currently the worlds most powerful rocket. The United Launch Alliance (ULA) Delta IV Heavy (D4H) has been the world’s mightiest rocket since the retirement of NASA’s Space Shuttles in 2011.

The Falcon Heavy sports about 2/3 the liftoff thrust of NASA’s Saturn V manned moon landing rockets – last launched in the 1970s.

SpaceX Falcon 9 blasts off with Intelsat 35e – 4th next gen ‘Epic’ TV and mobile broadband comsat for Intelsat – on July 5, 2017 at 7:38 p.m. EDT from Launch Complex 39A at NASA’s Kennedy Space Center in Florida. Credit: Ken Kremer/kenkremer.com

The Falcon Heavy is comprised of three Falcon 9 cores. The Delta IV Heavy is comprised of three Delta Common Core Boosters.

The combined trio of Falcon 9 cores will generate about 5.1 million pounds of liftoff thrust upon ignition from Launch Complex 39A at the Kennedy Space Center in Florida.

“With the ability to lift into orbit over 54 metric tons (119,000 lb)–a mass equivalent to a 737 jetliner loaded with passengers, crew, luggage and fuel–Falcon Heavy can lift more than twice the payload of the next closest operational vehicle, the Delta IV Heavy, at one-third the cost,” according to the SpaceX website.

“The nice thing is when you fully optimize it, it’s about two-and-a-half times the payload capability of a Falcon 9,” Musk notes. “It’s well over 100,000 pounds to LEO of payload capability, 50 tons. It can even get up a little higher than that if optimized.”

ULA Delta 4 Heavy rocket delivers NROL-37 spy satellite to orbit on June 11, 2016 from Space Launch Complex-37 on Cape Canaveral Air Force Station, Fl. Credit: Ken Kremer/kenkremer.com

The two stage Falcon Heavy stands more than 229.6 feet (70 meters) tall and is 39.9 feet wide (12.2 meters).

It weighs more than 3.1 million pounds (1.4 million kilograms).

Like the Falcon 9 it will be fueled with liquid oxygen and RP-1 kerosene propellants.

The thunder, power and roar of over 5 million pounds of liftoff thrust from the Falcon Heavy’s 27 engines is absolutely certain to be a thrilling, earth-shaking space spectacular !! Thus placing it in a class of its own unlike any US launch since NASA’s Saturn V and Space Shuttles rocketed to the high frontier from the same pad.

“I encourage people to come down to the Cape to see the first Falcon Heavy mission,” Musk said. “It’s guaranteed to be exciting.”

But before the Falcon Heavy can actually be rolled up to launch position at pad 39A, SpaceX must first complete repairs and refurbishment to nearby pad 40.

That Cape pad was heavily damaged nearly a year ago during a catastrophic launch pad explosion that took place in Sept. 2016 during a routine prelaunch fueling and static fire engine test of a Falcon 9 rocket with the Amos-6 commercial comsat payload bolted on top.

Pad 40 must achieve operational launch status again before SpaceX can commit to the Falcon Heavy launches at Pad 39A. Workers will also need to finish construction work at pad 39A to support the Heavy launches.

SpaceX Falcon 9 booster deploys quartet of landing legs moments before precision propulsive ground touchdown at Landing Zone 1 on Canaveral Air Force Station barely nine minutes after liftoff from Launch Complex 39A on 3 June 2017 from the Kennedy Space Center in Florida on the Dragon CRS-11 resupply mission to the International Space Station for NASA. Credit: Ken Kremer/Kenkremer.com

To date SpaceX has successfully demonstrated the recovery of thirteen boosters by land and sea.

Furthermore SpaceX engineers have advanced to the next step and successfully recycled, reflown and relaunched two ‘flight-proven first stages this year in March and June of 2017 from the Kennedy Space Center in Florida involving the SES-10 and BulgariaSat-1 launches respectively.

SpaceX CEO and Chief Designer Elon Musk and SES CTO Martin Halliwell exuberantly shake hands of congratulation following the successful delivery of SES-10 TV comsat to orbit using the first reflown and flight proven booster in world history at the March 30, 2017 post launch media briefing at NASA’s Kennedy Space Center in Florida. Credit: Ken Kremer/Kenkremer.com

The next SpaceX Falcon 9 launch is slated for Aug. 13 on the NASA contracted CRS-12 resupply mission to the ISS.

Watch for Ken’s onsite space mission reports direct from the Kennedy Space Center and Cape Canaveral Air Force Station, Florida.

Stay tuned here for Ken’s continuing Earth and Planetary science and human spaceflight news.

SpaceX Falcon 9 Booster leaning atop OCISLY droneship upon which it landed after 23 June launch from KSC floats into Port Canaveral, FL, on 29 June 2017, hauled by tugboat as seen from Jetty Park Pier. Credit: Ken Kremer/kenkremer.com

Blastoff of 2nd flight-proven SpaceX Falcon 9 with 1st geostationary communications for Bulgaria at 3:10 p.m. EDT on June 23, 2017, carrying BulgariaSat-1 to orbit from Launch Complex 39A at NASA’s Kennedy Space Center in Florida- as seen from the crawlerway. Credit: Ken Kremer/kenkremer.com

Posted on by Matt Williams

NASA Voyager Probes Still Going Strong After 40 Years

Earth's Greatest Hits: the Golden Record attached to the Voyager 1 and 2 spacecraft. Credit: NASA/JPL.

Forty years ago, the Voyager 1 and 2 missions began their journey from Earth to become the farthest-reaching missions in history. In the course of their missions, the two probes spent the next two decades sailing past the gas giants of Jupiter and Saturn. And while Voyager 1 then ventured into the outer Solar System, Voyager 2 swung by Uranus and Neptune, becoming the first and only probe in history to explore these worlds.

This summer, the probes will be marking the fortieth anniversary of their launch – on September 5th and August 20th, respectively. Despite having traveled for so long and reaching such considerable distances from Earth, the probes are still in contact with NASA and sending back valuable data. So in addition to being the most distant missions from Earth, they are the longest-running mission in history.

In addition to their distance and longevity, the Voyager spacecraft have also set numerous other records for robotic space missions. For example, in 2012, the Voyager 1 probe became the first and only spacecraft to have entered interstellar space. Voyage 2, meanwhile, is the only probe that has explored all four of the Solar System’s gas/ice giants – Jupiter, Saturn, Uranus and Neptune.

Voyager 2 Mission
The launch of the Voyager 2 probe, which took place on August 20th, 1977. Credit: NASA

Their discoveries also include the first active volcanoes beyond Earth – on Jupiter’s moon Io – the first evidence of a possible subsurface ocean on Europa, the dense atmosphere around Titan (the only body beyond Earth with a dense, nitrogen-rich atmosphere), the craggy surface of Uranus’ “Frankenstein Moon” Miranda, and the ice plume geysers of Neptune’s largest moon, Triton.

These accomplishments have had immeasurable benefits for planetary science, astronomy and space exploration. They’ve also paved the way for future missions, such as the Galileo and Juno probes, the Cassini-Huygens mission, and the New Horizons spacecraft. As Thomas Zurbuchen, the associate administrator for NASA’s Science Mission Directorate (SMD), said in a recent press statement:

“I believe that few missions can ever match the achievements of the Voyager spacecraft during their four decades of exploration. They have educated us to the unknown wonders of the universe and truly inspired humanity to continue to explore our solar system and beyond.”

But what is perhaps most memorable about the Voyager missions is the special cargo they carry. Each spacecraft carries what is known as the Golden Record, a collection of sounds, pictures and messages that tell of Earth, human history and culture. These records were intended to serve as a sort of time capsule and/or message to any civilizations that retrieved them, should they ever be recovered.

Each of the two Voyager spacecraft launched in 1977 carry a 12-inch gold-plated phonograph record with images and sounds from Earth. Credit: NASA

As noted, both ships are still in contact with NASA and sending back mission data. The Voyager 1 probe, as of the writing of this article, is about 20.9 billion km (13 billion mi; 140 AU) from Earth. As it travels northward out of the plane of the planets and into interstellar space, the probe continues to send back information about cosmic rays – which are about four times as abundant in interstellar space than around Earth.

From this, researchers have learned that the heliosphere – the region that contains the Solar System’s planets and solar wind – acts as a sort of radiation shield. Much in the say that Earth’s magnetic field protects us from solar wind (which would otherwise strip away our atmosphere), the heliopause protects the Solar planets from atomic nuclei that travel at close to the speed of light.

Voyager 2, meanwhile, is currently about 17.7 billion km (11 billion mi; 114.3 AU) from Earth. It is traveling south out of the plane of the planets, and is expected to enter interstellar space in a few years. And much like Voyager 1, it is also studying how the heliosphere interacts with the surroundings interstellar medium, using a suite of instruments that measure charged particles, magnetic fields, radio waves and solar wind plasma.

Once Voyager 2 crosses into interstellar space, both probes will be able to sample the medium from two different locations simultaneously. This is expected to tell us much about the magnetic environment that encapsulates our system, and will perhaps teach us more about the history and formation of the Solar System. On top of that, it will let us know what kinds of hazards a possible interstellar mission will have to contend with.

Illustration showing how NASA’s Hubble Space Telescope is looking along the paths of NASA’s Voyager 1 and 2 spacecraft as they journey through the solar system and into interstellar space. Credit: NASA/ESA/Z. Levy (STScI)

The fact that the two probes are still active after all this time is nothing short of amazing. As Edward Stone – the David Morrisroe Professor of Physics at Caltech, the former VP and Director of NASA’s Jet Propulsion Laboratory, and the Voyager project scientist – said:

“None of us knew, when we launched 40 years ago, that anything would still be working, and continuing on this pioneering journey. The most exciting thing they find in the next five years is likely to be something that we didn’t know was out there to be discovered.”

Keeping the probes going has also been a challenge since the amount of power they generate decreases at a rate of about four watts per year. This has required that engineers learn how to operate the twin spacecraft with ever-decreasing amounts of power, which has forced them to consult documents that are decades old in order to understand the probes’ software and command functions.

Luckily, it has also given former NASA engineers who worked on the Voyager probes the opportunity to offer their experience and expertise. At present, the team that is operating the spacecraft estimate that the probes will run out of power by 2030. However, they will continue to drift along their trajectories long after they do so, traveling at a speed of 48,280 km per hour (30,000 mph) and covering a single AU every 126 days.

The Voyager 1 spacecraft has started to transverse what JPL has dubbed as a “cosmic purgatory” between our solar system – and interstellar space. Credit: NASA/JPL

At this rate, they will be within spitting distance of the nearest star in about 40,000 years, and will have completed an orbit of the Milky Way within 225 million years. So its entirely possible that someday, the Golden Records will find their way to a species capable of understanding what they represent. Then again, they might find their way back to Earth someday, informing our distant, distant relatives about life in the 20th century.

And if the craft avoid any catastrophic collisions and can survive in the interstellar medium of space, it is likely that they will continue to be emissaries for humanity long after humanity is dead. It’s good to leave something behind!

Further Reading: NASA

Posted on by Matt Williams

Bad News For Proxima b: An Earth-Like Atmosphere Might Not Survive There

Artist’s impression of Proxima b, which was discovered using the Radial Velocity method. Credit: ESO/M. Kornmesser

Back in of August of 2016, the existence of an Earth-like planet right next door to our Solar System was confirmed. To make matters even more exciting, it was confirmed that this planet orbits within its star’s habitable zone too. Since that time, astronomers and exoplanet-hunters have been busy trying to determine all they can about this rocky planet, known as Proxima b. Foremost on everyone’s mind has been just how likely it is to be habitable.

However, numerous studies have emerged since that time that indicate that Proxima b, given the fact that it orbits an M-type (red dwarf), would have a hard time supporting life. This was certainly the conclusion reached in a new study led by researchers from NASA’s Goddard Space Flight Center. As they showed, a planet like Proxima b would not be able to retain an Earth-like atmosphere for very long.

Red dwarf stars are the most common in the Universe, accounting for an estimated 70% of stars in our galaxy alone. As such, astronomers are naturally interested in knowing just how likely they are at supporting habitable planets. And given the distance between our Solar System and Proxima Centauri – 4.246 light years – Proxima b is considered ideal for studying the habitability of red dwarf star systems.

This infographic compares the orbit of the planet around Proxima Centauri (Proxima b) with the same region of the Solar System. Credit: Pale Red Dot

On top of all that, the fact that Proxima b is believed to be similar in size and composition to Earth makes it an especially appealing target for research. The study was led by Dr. Katherine Garcia-Sage of NASA’s Goddard Space Flight Center and the Catholic University of America in Washington, DC. As she told Universe Today via email:

“So far, not many Earth-sized exoplanets have been found orbiting in the temperate zone of their star. That doesn’t mean they don’t exist – larger planets are found more often because they are easier to detect – but Proxima b is of interest because it’s not only Earth-sized and at the right distance from its star, but it’s also orbiting the closest star to our Solar System.”

For the sake of determining if Proxima b could be habitable, the research team sought to address the chief concerns facing rocky planets that orbit red dwarf stars. These include the planet’s distance from its stars, the variability of red dwarfs, and the presence (or absence) of magnetic fields. Distance is of particular importance since habitable zones (aka. temperate zones) around red dwarfs are much closer and tighter.

“Red dwarfs are cooler than our own Sun, so the temperate zone is closer to the star than Earth is to the Sun,” said Dr. Garcia-Sage. “But these stars may be very magnetically active, and being so close to a magnetically active star means that these planets are in a very different space environment than what the Earth experiences. At those distances from the star, the ultraviolet and x-ray radiation may be quite large. The stellar wind may be stronger. There could be stellar flares and energetic particles from the star that ionize and heat the upper atmosphere.”

At one time, Mars had a magnetic field similar to Earth, which prevented its atmosphere from being stripped away. Credit: NASA

In addition, red dwarf stars are known for being unstable and variable in nature when compared to our Sun. As such, planets orbiting in close proximity would have to contend with flare ups and intense solar wind, which could gradually strip away their atmospheres. This raises another important aspect of exoplanet habitability research, which is the presence of magnetic fields.

To put it simply, Earth’s atmosphere is protected by a magnetic field that is driven by a dynamo effect in its outer core. This “magnetosphere” has prevented solar wind from stripping our atmosphere away, thus giving life a chance to emerge and evolve. In contrast, Mars lost its magnetosphere roughly 4.2 billion years ago, which led to its atmosphere being depleted and its surface becoming the cold, desiccated place it is today.

To test Proxima b’s potential habitability and capacity to retain liquid surface water, the team therefore assumed the presence of an Earth-like atmosphere and a magnetic field around the planet. They then accounted for the enhanced radiation coming from Proxima b. This was provided by the Harvard Smithsonian Center for Astrophysics (CfA), where researchers determined the ultraviolet and x-ray spectrum of Proxima Centauri for this project.

From all of this, they constructed models that began to calculate the rate of atmospheric loss, using Earth’s atmosphere as a template. As Dr. Garcia-Sage explained:

“At Earth, the upper atmosphere is ionized and heated by ultraviolet and x-ray radiation from the Sun. Some of these ions and electrons escape from the upper atmosphere at the north and south poles. We have a model that calculates how fast the upper atmosphere is lost through these processes (it’s not very fast at Earth)… We then used that radiation as the input for our model and calculated a range of possible escape rates for Proxima Centauri b, based on varying levels of magnetic activity.”

Artist’s impression of the surface of the planet Proxima b orbiting the red dwarf star Proxima Centauri. The double star Alpha Centauri AB is visible to the upper right of Proxima itself. Credit: ESO

What they found was not very encouraging. In essence, Proxima b would not be able to retain an Earth-like atmosphere when subjected to Proxima Centauri’s intense radiation, even with the presence of a magnetic field. This means that unless Proxima b has had a very different kind of atmospheric history than Earth, it is most likely a lifeless ball of rock.

However, as Dr. Garcia-Sage put it, there are other factors to consider which their study simply can’t account for:

“We found that atmospheric losses are much stronger than they are at Earth, and the for high levels of magnetic activity that we expect at Proxima b, the escape rate was fast enough that an entire Earth-like atmosphere could be lost to space. That doesn’t take into account other things like volcanic activity or impacts with comets that might be able to replenish the atmosphere, but it does mean that when we’re trying to understand what processes shaped the atmosphere of Proxima b, we have to take into account the magnetic activity of the star. And understanding the atmosphere is an important part of understanding whether liquid water could exist on the surface of the planet and whether life could have evolved.”

So it’s not all bad news, but it doesn’t inspire a lot of confidence either. Unless Proxima b is a volcanically-active planet and subject to a lot of cometary impacts, it is not likely be temperate, water-bearing world. Most likely, its climate will be analogous to Mars – cold, dry, and with water existing mostly in the form of ice. And as for indigenous life emerging there, that’s not too likely either.

These and other recent studies have painted a rather bleak picture about the habitability of red dwarf star systems. Given that these are the most common types of stars in the known Universe, the statistical likelihood of finding a habitable planet beyond our Solar System appears to be dropping. Not exactly good news at all for those hoping that life will be found out there within their lifetimes!

But it is important to remember that what we can say definitely at this point about extra-solar planets is limited. In the coming years and decades, next-generation missions – like the James Webb Space Telescope (JWST) and the Transiting Exoplanet Survey Satellite (TESS) –  are sure to paint a more detailed picture. In the meantime, there’s still plenty of stars in the Universe, even if most of them are extremely far away!

Further Reading: The Astrophysical Journal Letters

Posted on by Matt Williams

Need a Job? NASA is Looking for a New Planetary Protection Officer

In the future, planetary protection (where we ensure that missions do not contaminate other words with Earth-borne organisms) will be especially important. Credit: NASA, JPL-Caltech

NASA has always had its fingers in many different pies. This should come as no surprise, since the advancement of science and the exploration of the Universe requires a multi-faceted approach. So in addition to studying Earth and distant planets, the also study infectious diseases and medical treatments, and ensuring that food, water and vehicles are safe. But protecting Earth and other planets from contamination, that’s a rather special job!

For decades, this responsibility has fallen to the NASA Office of Planetary Protection, the head of which is known as the Planetary Protection Officer (PPO). Last month, NASA announced that it was looking for a new PPO, the person whose job it will be to ensure that future missions to other planets don’t contaminate them with microbes that have come along for the ride, and that return missions don’t bring extra-terrestrial microbes back to Earth.

Since the beginning of the Space Age, federal agencies have understood that any and all missions carried with them the risk of contamination. Aside from the possibility that robotic or crewed missions might transport Earth microbes to foreign planets (and thus disrupt any natural life cycles there), it was also understood that missions returning from other bodies could bring potentially harmful organisms back to Earth.

The US won the space race against its adversary, the USSR. The image of the American flag planted on the Moon, being saluted by an American astronaut, must have caused great consternation in the Kremlin. Will SpaceX's mission to Mars cause the same consternation? Will Russia and other nations use the mission to remind the US of their Outer Space Treaty obligations? Image: NASA
Back when NASA was still in the midst of the Apollo Program, it was decided that steps needed to be taken to ensure that missions to other bodies did not cause contaminated. Credit: NASA

As such, the Office of Planetary Protection was established in 1967 to ensure that these risks were mitigated using proper safety and sterilization protocols. This was shortly after the United Nation’s Office of Outer Space Affairs (UNOOSA) drafted the Outer Space Treaty, which was signed by the United States, the United Kingdom, and the Soviet Union (as of 2017, 107 countries have become party to the treaty).

The goals of the Office of Planetary Protection are consistent with Article IX of the Outer Space Treaty; specifically, the part which states:

“States Parties to the Treaty shall pursue studies of outer space, including the Moon and other celestial bodies, and conduct exploration of them so as to avoid their harmful contamination and also adverse changes in the environment of the Earth resulting from the introduction of extraterrestrial matter and, where necessary, shall adopt appropriate measures for this purpose.”

The office and its practices are also consistent with NASA’s internal policies. These include NASA Policy Directive (NPR) 8020.12D: “Planetary Protection Provisions for Robotic Extraterrestrial Missions”, and 8020.7: “Biological Contamination Control for Outbound and Inbound Planetary Spacecraft”, which require that all missions comply with protection procedures.

For decades, these directives have been followed to ensure that missions to the Moon, Mars and the Outer Solar System did not threaten these extra-terrestrial environments. For example, after eight years studying Jupiter and its largest moons, the Galileo probe was deliberately crashed into Jupiter’s atmosphere to ensure that none of its moons (which could harbor life beneath their icy surfaces) were contaminated by Earth-based microbes.

Artist’s concept of the Galileo space probe passing through the Jupiter system. Credit: NASA

The same procedure will be followed by the Juno mission, which is currently in orbit around Jupiter. Barring a possible mission extension, the probe is scheduled to be deorbited after conducting a total of 12 orbits of the gas giant. This will take place in July of 2018, at which point, the craft will burn up to avoid contaminating the Jovian moons of Europa, Ganymede and Callisto.

The same holds true for the Cassini spacecraft, which is currently passing between Saturn and its system of rings, as part of the mission’s Grand Finale. When this phase of its mission is complete – on September 15th, 2017 – the probe will be deorbited into Saturn’s atmosphere to prevent any microbes from reaching Enceladus, Titan, Dione, moons that may also support life in their interiors (or in Titan’s case, even on its surface!)

To be fair, the position of a Planetary Protection Officer is not unique to NASA. The European Space Agency (ESA), the Japanese Aerospace and Exploration Agency (JAXA) and other space agencies have similar positions. However, it is only within NASA and the ESA that it is considered to be a full-time job. The position is held for three years (with a possible extension to five) and is compensated to the tune of $124,406 to $187,000 per year.

The job, which can be applied for on USAJOBS.gov (and not through the Office of Planetary Protection), will remain open until August 18th, 2017. According to the posting, the PPO will be responsible for:

  • Leading planning and coordinating activities related to NASA mission planetary protection needs.
  • Leading independent evaluation of, and providing advice regarding, compliance by robotic and human spaceflight missions with NASA planetary protection policies, statutory requirements and international obligations.
  • Advising the Chief, SMA and other officials regarding the merit and implications of programmatic decisions involving risks to planetary protection objectives.
  • In coordination with relevant offices, leading interactions with COSPAR, National Academies, and advisory committees on planetary protection matters.
  • Recommending and leading the preparation of new or revised NASA standards and directives in accordance with established processes and guidelines.

What’s more, the fact that NASA is advertising the position is partly due to some recent changes to the role. As Catharine Conley*, NASA’s only planetary protection officer since 2014, indicated in a recent interview with Business Insider: “This new job ad is a result of relocating the position I currently hold to the Office of Safety and Mission Assurance, which is an independent technical authority within NASA.”

While the position has been undeniably important in the past, it is expected to become of even greater importance given NASA’s planned activities for the future. This includes NASA’s proposed “Journey to Mars“, a crewed mission which will see humans setting foot on the Red Planet sometime in the 2030s. And in just a few years time, the Mars 2020 rover is scheduled to begin searching the Martian surface for signs of life.

As part of this mission, the Mars 2020 rover will collect soil samples and place them in a cache to be retrieved by astronauts during the later crewed mission. Beyond Mars, NASA also hopes to conduct mission to Europa, Enceladus and Titan to look for signs of life. Each of these worlds have the necessary ingredients, which includes the prebiotic chemistry and geothermal energy necessary to support basic lifeforms.

Given that we intend to expand our horizons and explore increasingly exotic environments in the future – which could finally lead to the discovery of life beyond Earth – it only makes sense that the role of the Planetary Protection Officer become more prominent. If you think you’ve got the chops for it, and don’t mind a six-figure salary, be sure to apply soon!

*According to BI, Conley has not indicated if she will apply for the position again.

Further Reading: Business Insider, USAJOBS