BIG BANG - Next Time You’re Late To Work, Blame Dark Energy!

Next Time You’re Late To Work, Blame Dark Energy!:

Ever since Lemaitre and Hubble's first proposed it in the 1920s, scientists and astronomers have been aware that the Universe is expanding. And from these observations, cosmological theories like the Big Bang Theory and the "Arrow of Time" emerged. Whereas the former addresses the origins and evolution of our Universe, the latter argues that the flow of time in one-direction and is linked to the expansion of space.



For many years, scientists have been trying to ascertain why this is. Why does time flow forwards, but not backwards? According to new study produced by a research team from the Yerevan Institute of Physics and Yerevan State University in Armenia, the influence of dark energy may be the reason for the forward-flow of time, which may make one-directional time a permanent feature of our universe.



Today, theories like the Arrow of Time and the expansion of the universe are considered fundamental facts about the Universe. Between measuring time with atomic clocks, observing the red shift of galaxies, and created detailed 3D maps that show the evolution of our Universe over the course of billions of years, one can see how time and the expansion of space are joined at the hip.







The question of why this is the case though is one that has continued to frustrate physicists. Certain fundamental forces, like gravity, are not governed by time. In fact, one could argue without difficulty that Newton's Laws of Motion and quantum mechanics work the same forwards or backwards. But when it comes to things on the grand scale like the behavior of planets, stars, and entire galaxies, everything seems to come down to the Second Law of Thermodynamics.



This law, which states that the total chaos (aka. entropy) of an isolated system always increases over time, the direction in which time moves is crucial and non-negotiable, has come to be accepted as the basis for the Arrow of Time. In the past, some have ventured that if the Universe began to contract, time itself would begin to flow backwards. However, since the 1990s and the observation that the Universe has been expanding at an accelerating rate, scientists have come to doubt that this.



If, in fact, the Universe is being driven to greater rates of expansion - the predominant explanation is that "Dark Energy" is what is driving it - then the flow of time will never cease being one way. Taking this logic a step further, two Armenian researchers - Armen E. Allahverdyan of the Center for Cosmology and Astrophysics at the Yerevan Institute of Physics and Vahagn G. Gurzadyan of Yerevan State University - argue that dark energy is the reason why time always moves forward.



In their paper, titled "Time Arrow is Influenced by the Dark Energy", they argue that dark energy accelerating the expansion of the universe supports the asymmetrical nature of time. Often referred to as the "cosmological constant" - referring to Einstein's original theory about a force which held back gravity to achieve a static universe - dark energy is now seen as a "positive" constant, pushing the Universe forward, rather than holding it back.







To test their theory, Allahverdyan and Gurzadyan used a large scale scenario involving gravity and mass - a planet with increasing mass orbiting a star. What they found was that if dark energy had a value of 0 (which is what physicists thought before the 1990s), or if gravity were responsible for pulling space together, the planet would simply orbit the star without any indication as to whether it was moving forwards or backwards in time.



But assuming that the value of dark energy is a positive (as all the evidence we've seen suggests) then the planet would eventually be thrown clear of the star. Running this scenario forward, the planet is expelled because of its increasing mass; whereas when it is run backwards, the planet closes in on the star and is captured by it's gravity.



In other words, the presence of dark energy in this scenario was the difference between having an "arrow of time" and not having one. Without dark energy, there is no time, and hence no way to tell the difference between past, present and future, or whether things are running in a forward direction or backwards.



But of course, Allahverdyan and Gurzadyan were also sure to note in their study that this is a limited test and doesn't answer all of the burning questions. "We also note that the mechanism cannot (and should not) explain all occurrences of the thermodynamic arrow," they said. "However, note that even when the dark energy (cosmological constant) does not dominate the mean density (early universe or today’s laboratory scale), it still exists."



https://youtu.be/T1JknKr99_4



Limited or not, this research is representative of some exciting new steps that astrophysicists have been taking of late. This involves not only questioning the origins of dark energy and the expansion force it creates, but also questioning its implication in basic physics. In so doing, researchers may finally be able to answer the age-old question about why time exists, and whether or not it can be manipulated (i.e. time travel!)



Further Reading: Physical Review E

The post Next Time You’re Late To Work, Blame Dark Energy! appeared first on Universe Today.

COLD STARS ? Can Stars Be Cold ?

Can Stars Be Cold?:

If you’ve heard me say “oot and aboot”, you know I’m a Canadian. And we Canadians are accustomed to a little cold. Okay, a LOT of cold. It’s not so bad here on the West Coast, but folks from Winnepeg can endure temperatures colder than the surface of Mars.  Seriously, who lives like that?

And on one of those cold days, even on a clear sunny day, the Sun is pointless and worthless. As the bone chilling cold numbs your fingers and toes, it’s as if the Sun itself has gone cold, sapping away all the joy and happiness in the world. And don’t get me started about the rain. Clearly, I need to take more tropical vacations.

But we know the Sun isn’t cold at all, it’s just that the atmosphere around you feels cold. The surface of the Sun is always the same balmy 5,500 degrees Celsius. Just to give you perspective, that’s hot enough to melt iron, nickel. Even carbon melts at 2500 C. So, no question, the Sun is hot.

The Sun – It’s pretty hot. Credit: NASA/SDO.

And you know that the Sun is hot because it’s bright. There are actually photons streaming from the Sun at various wavelengths, from radio, infrared, through the visible spectrum, and into the ultraviolet. There are even X-ray photons blasting off the Sun.

If the Sun was cooler, it would look redder, just like a cooler red dwarf star, and if the Sun was hotter, it would appear more blue. But could you have a star that’s cooler, or even downright cold?

The answer is yes, you just have to be willing to expand your definition of what a star is.

Under the normal definition, a star is a collection of hydrogen, helium and other elements that came together by mutual gravity. The intense gravitational pressure of all that mass raised temperatures at the core of the star to the point that hydrogen could be fused into helium. This reaction releases more energy than it takes, which causes the Sun to emit energy.

The coolest possible red dwarf star, one with only 7.5% the mass of the Sun, will still have a temperature of about 2,300 C, a little less than the melting point of carbon.

But if a star doesn’t have enough mass to ignite fusion, it becomes a brown dwarf. It’s heated by the mechanical action of all that mass compressing inward, but it’s cooler. Average brown dwarfs will be about 1,700 C, which actually, is still really hot. Like, molten rock hot.

This artist’s conception illustrates the brown dwarf named 2MASSJ22282889-431026. Credit: NASA/JPL-Caltech

Brown dwarfs can actually get a lot cooler, a new class of these “stars” were discovered by the WISE Space Observatory that start at 300 degrees, and go all the way down to about 27 degrees, or room temperature. This means there are stars out there that you could touch.

Except you couldn’t, because they’d still have more than a dozen times the mass of Jupiter, and would tear your arm off with their intense gravity. And anyway, they don’t a solid surface. No, you can’t actually touch them.

That’s about as cold as stars get, today, in the Universe.

But if you’re willing to be very very patient, then it’s a different story. Our own Sun will eventually run out of fuel, die and become a white dwarf. It’ll start out hot, but over the eons, it’ll cool down, eventually becoming the same temperature as the background level of the Universe – just a few degrees above absolute zero. Astronomers call these black dwarfs.

We’re talking a long long time, though, in fact, in the 13.8 billion years that the Universe has been around, no white dwarfs have had enough time to cool down significantly. In fact, it would take about a quadrillion years to get within a few degrees of the cosmic microwave background radiation temperature.

The post Can Stars Be Cold? appeared first on Universe Today.

EARTH PLANET - 10 Interesting Facts About Earth

10 Interesting Facts About Earth:

Planet Earth. That shiny blue marble that has fascinated humanity since they first began to walk across its surface. And why shouldn't it fascinate us? In addition to being our home and the place where life as we know it originated, it remains the only planet we know of where life thrives. And over the course of the past few centuries, we have learned much about Earth, which has only deepened our fascination with it.



But how much does the average person really know about the planet Earth? You've lived on Planet Earth all of your life, but how much do you really know about the ground underneath your feet? You probably have lots of interesting facts rattling around in your brain, but here are 10 more interesting facts about Earth that you may, or may not know.

1. Plate Tectonics Keep the Planet Comfortable:

Earth is the only planet in the Solar System with plate tectonics. Basically, the outer crust of the Earth is broken up into regions known as tectonic plates. These are floating on top of the magma interior of the Earth and can move against one another. When two plates collide, one plate will subduct (go underneath another), and where they pull apart, they will allow fresh crust to form.







This process is very important, and for a number of reasons. Not only does it lead to tectonic resurfacing and geological activity (i.e. earthquakes, volcanic eruptions, mountain-building, and oceanic trench formation), it is also intrinsic to the carbon cycle. When microscopic plants in the ocean die, they fall to the bottom of the ocean.

Over long periods of time, the remnants of this life, rich in carbon, are carried back into the interior of the Earth and recycled. This pulls carbon out of the atmosphere, which makes sure we don't suffer a runaway greenhouse effect, which is what happened on Venus. Without the action of plate tectonics, there would be no way to recycle this carbon, and the Earth would become an overheated, hellish place.

2. Earth is Almost a Sphere:

Many people tend to think that the Earth is a sphere. In fact, between the 6th cenury BCE and the modern era, this remained the scientific consensus. But thanks to modern astronomy and space travel, scientists have since come to understand that the Earth is actually shaped like a flattened sphere (aka. an oblate spheroid).



This shape is similar to a sphere, but where the poles are flattened and the equator bulges. In the case of the Earth, this bulge is due to our planet's rotation. This means that the measurement from pole to pole is about 43 km less than the diameter of Earth across the equator. Even though the tallest mountain on Earth is Mount Everest, the feature that's furthest from the center of the Earth is actually Mount Chimborazo in Ecuador.

3. Earth is Mostly Iron, Oxygen and Silicon:

If you could separate the Earth out into piles of material, you'd get 32.1 % iron, 30.1% oxygen, 15.1% silicon, and 13.9% magnesium. Of course, most of this iron is actually located at the core of the Earth. If you could actually get down and sample the core, it would be 88% iron. And if you sampled the Earth's crust, you'd find that 47% of it is oxygen.

4. 70% of the Earth's Surface is Covered in Water:

When astronauts first went into the space, they looked back at the Earth with human eyes for the first time. Based on their observations, the Earth acquired the nickname the "Blue Planet:. And it's no surprise, seeing as how 70% of our planet is covered with oceans. The remaining 30% is the solid crust that is located above sea level, hence why it is called the "continental crust".

5. The Earth's Atmosphere Extends to a Distance of 10,000 km:

Earth's atmosphere is thickest within the first 50 km from the surface or so, but it actually reaches out to about 10,000 km into space. It is made up of five main layers - the Troposphere, the Stratosphere, the Mesosphere, the Thermosphere, and the Exosphere. As a rule, air pressure and density decrease the higher one goes into the atmosphere and the farther one is from the surface.







The bulk of the Earth's atmosphere is down near the Earth itself. In fact, 75% of the Earth's atmosphere is contained within the first 11 km above the planet's surface. However, the outermost layer (the Exosphere) is the largest, extending from the exobase - located at the top of the thermosphere at an altitude of about 700 km above sea level - to about 10,000 km (6,200 mi). The exosphere merges with the emptiness of outer space, where there is no atmosphere.



The exosphere is mainly composed of extremely low densities of hydrogen, helium and several heavier molecules - including nitrogen, oxygen and carbon dioxide. The atoms and molecules are so far apart that the exosphere no longer behaves like a gas, and the particles constantly escape into space. These free-moving particles follow ballistic trajectories and may migrate in and out of the magnetosphere or with the solar wind.



Want more planet Earth facts? We're halfway through. Here come 5 more!

6. The Earth's Molten Iron Core Creates a Magnetic Field:

The Earth is like a great big magnet, with poles at the top and bottom near to the actual geographic poles. The magnetic field it creates extends thousands of kilometers out from the surface of the Earth - forming a region called the "magnetosphere". Scientists think that this magnetic field is generated by the molten outer core of the Earth, where heat creates convection motions of conducting materials to generate electric currents.







Be grateful for the magnetosphere. Without it, particles from the Sun's solar wind would hit the Earth directly, exposing the surface of the planet to significant amounts of radiation. Instead, the magnetosphere channels the solar wind around the Earth, protecting us from harm. Scientists have also theorized that Mars' thin atmosphere is due to it having a weak magnetosphere compared to Earth's, which allowed solar wind to slowly strip it away.

7. Earth Doesn't Take 24 Hours to Rotate on its Axis:

It actually takes 23 hours, 56 minutes and 4 seconds for the Earth to rotate once completely on its axis, which astronomers refer to as a Sidereal Day. Now wait a second, doesn't that mean that a day is 4 minutes shorter than we think it is? You'd think that this time would add up, day by day, and within a few months, day would be night, and night would be day.



But remember that the Earth orbits around the Sun. Every day, the Sun moves compared to the background stars by about 1° - about the size of the Moon in the sky. And so, if you add up that little motion from the Sun that we see because the Earth is orbiting around it, as well as the rotation on its axis, you get a total of 24 hours.



This is what is known as a Solar Day, which - contrary to a Sidereal Day - is the amount of time it takes the Sun to return to the same place in the sky. Knowing the difference between the two is to know the difference between how long it takes the stars to show up in the same spot in the sky, and the it takes for the sun to rise and set once.



https://youtu.be/uZnaAo6tin8

8. A year on Earth isn't 365 days:

It's actually 365.2564 days. It's this extra .2564 days that creates the need for a Leap Year once ever four years. That's why we tack on an extra day in February every four years - 2004, 2008, 2012, etc. The exceptions to this rule is if the year in question is divisible by 100 (1900, 2100, etc), unless it divisible by 400 (1600, 2000, etc).

9. Earth has 1 Moon and 2 Co-Orbital Satellites:

As you're probably aware, Earth has 1 moon (aka. The Moon). Plenty is known about this body and we have written many articles about it, so we won't go into much detail there. But did you know there are 2 additional asteroids locked into a co-orbital orbits with Earth? They're called 3753 Cruithne and 2002 AA₂₉, which are part of a larger population of asteroids known as Near-Earth Objects (NEOs).



The asteroid known as 3753 Cruithne measures 5 km across, and is sometimes called "Earth's second moon". It doesn't actually orbit the Earth, but has a synchronized orbit with our home planet. It also has an orbit that makes it look like it's following the Earth in orbit, but it's actually following its own, distinct path around the Sun.



https://youtu.be/yThdl3fVuaE



Meanwhile, 2002 AA₂₉ is only 60 meters across and makes a horseshoe orbit around the Earth that brings it close to the planet every 95 years. In about 600 years, it will appear to circle Earth in a quasi-satellite orbit. Scientists have suggested that it might make a good target for a space exploration mission.

10. Earth is the Only Planet Known to Have Life:

We've discovered past evidence of water and organic molecules on Mars, and the building blocks of life on Saturn's moon Titan. We can see amino acids in nebulae in deep space. And scientists have speculated about the possible existence of life beneath the icy crust of Jupiter's moon Europa and Saturn's moon Titan. But Earth is the only place life has actually been discovered.



But if there is life on other planets, scientists are building the experiments that will help find it. For instance, NASA just announced the creation of the Nexus for Exoplanet System Science (NExSS), which will spend the coming years going through the data sent back by the Kepler space telescope (and other missions that have yet to be launched) for signs of life on extra-solar planets.







Giant radio dishes are currently scan distant stars, listening for the characteristic signals of intelligent life reaching out across interstellar space. And newer space telescopes, such as NASA's James Webb Telescope, the Transiting Exoplanet Survey Satellite (TESS), and the European Space Agency's Darwin mission might just be powerful enough to sense the presence of life on other worlds.



But for now, Earth remains the only place we know of where there's life. Now that is an interesting fact!



We have written many interesting articles about planet Earth here on Universe Today. Here's What is the Highest Place on Earth?, What is the Diameter of the Earth?, What is the Closest Planet to Earth?, What is the Surface Temperature of Earth? and The Rotation of the Earth?



Other articles include how fast the Earth rotates, and here's an article about the closest star to Earth. If you'd like more info on Earth, check out NASA's Solar System Exploration Guide on Earth. And here's a link to NASA's Earth Observatory.



And there's even an Astronomy Cast episode on the subject of planet Earth.

The post 10 Interesting Facts About Earth appeared first on Universe Today.

NEPTUNE PLANET - What is the Coldest Planet of Our Solar System?

What is the Coldest Planet of Our Solar System?:

The Solar System is pretty huge place, extending from our Sun at the center all the way out to the Kuiper Cliff - a boundary within the Kuiper Belt that is located 50 AU from the Sun. As a rule, the farther one ventures from the Sun, the colder and more mysterious things get. Whereas temperatures in the inner Solar System are enough to burn you alive or melt lead, beyond the "Frost Line", they get cold enough to freeze volatiles like ammonia and methane.



So what is the coldest planet of our Solar System? In the past, the title for "most frigid body" went to Pluto, as it was the farthest then-designated planet from the Sun. However, due to the IAU's decision in 2006 to reclassify Pluto as a "dwarf planet", the title has since passed to Neptune. As the eight planet from our Sun, it is now the outermost planet in the Solar System, and hence the coldest.

Orbit and Distance:

With an average distance (semi-major axis) of 4,504,450,000 km (2,798,935,466.87 mi or 30.11 AU), Neptune is the farthest planet from the Sun. The planet has a very minor eccentricity of 0.0086, which means that its orbit around the Sun varies from a distance of 29.81 AU (4.459 x 10⁹ km) at perihelion to 30.33 AU (4.537 x 10⁹ km) at aphelion.







Because Neptune’s axial tilt (28.32°) is similar to that of Earth (~23°) and Mars (~25°), the planet experiences similar seasonal changes. Combined with its long orbital period, this means that the seasons last for forty Earth years. Also owing to its axial tilt being comparable to Earth’s is the fact that the variation in the length of its day over the course of the year is not any more extreme than it is on Earth.

Average Temperature:

When it comes to ascertaining the average temperature of a planet, scientists rely on temperature variations measured from the surface. As a gas/ice giant, Neptune has no surface, per se. As a result, scientists rely on temperature readings from where the atmospheric pressure is equal to 1 bar (100 kPa), the equivalent to atmospheric pressure at sea level here on Earth.



On Neptune, this area of the atmosphere is just below the upper level clouds. Pressures in this region range between 1 and 5 bars (100 – 500 kPa), and temperature reach a high of 72 K (-201.15 °C; -330 °F). At this temperature, conditions are suitable for methane to condense, and clouds of ammonia and hydrogen sulfide are thought to form (which is what gives Neptune its characteristically dark cyan coloring).



Farther into space, where pressures drop to about 0.1 bars (10 kPa), temperatures decrease to their low of around 55 K (-218 °C; -360 °F). Further into the planet, pressures increase dramatically, which also leads to a dramatic increase in temperature. At its core, Neptune reaches temperatures of up to 7273 K (7000 °C; 12632 °F), which is comparable to the surface of the Sun.







The huge temperature differences between Neptune’s center and its surface (along with its differential rotation) create huge wind storms, which can reach as high as 2,100 km/hour, making them the fastest in the Solar System. The first to be spotted was a massive anticyclonic storm measuring 13,000 x 6,600 km and resembling the Great Red Spot of Jupiter.



Known as the Great Dark Spot, this storm was not spotted five later (Nov. 2nd, 1994) when the Hubble Space Telescope looked for it. Instead, a new storm that was very similar in appearance was found in the planet's northern hemisphere, suggesting that these storms have a shorter lifespan than Jupiter's. The Scooter is another storm, a white cloud group located farther south than the Great Dark Spot.



This nickname first arose during the months leading up to the Voyager 2 encounter in 1989, when the cloud group was observed moving at speeds faster than the Great Dark Spot. The Small Dark Spot, a southern cyclonic storm, was the second-most-intense storm observed during the 1989 encounter. It was initially completely dark; but as Voyager 2 approached the planet, a bright core developed and could be seen in most of the highest-resolution images.

Temperature Anomalies:

Despite being 50% further from the Sun than Uranus - which orbits the Sun at an average distance of 2,875,040,000 km (1,786,467,032.5 mi or 19.2184 AU) - Neptune receives only 40% of the solar radiation that Uranus does. In spite of that, the two planets’ surface temperatures are surprisingly close, with Uranus experiencing an average "surface" temperature of 76 K (-197.2 °C)







And while temperatures similarly increase the further one ventures into the core, the discrepancy is larger. Uranus only radiates 1.1 times as much energy as it receives from the Sun, whereas Neptune radiates about 2.61 times as much. Neptune is the farthest planet from the Sun, yet its internal energy is sufficient to drive the fastest planetary winds seen in the Solar System.



One would expect Neptune to be much colder than Uranus, and the mechanism for this remains unknown. However, astronomers have theorized that  Neptune's higher internal temperature (and the exchange of heat between the core and outer layers) might be the reason for why Neptune isn't significantly colder than Uranus.



As already noted, Pluto's surface temperatures do get to being lower than Neptune's. Between its greater distance from the Sun, and the fact that it is not a gas/ice giant (so therefore doesn't have extreme temperatures at its core) means that it experiences temperatures between a high of 55 K (-218 °C; -360 °F)and a low of 33 K (-240 °C; -400 °F). However, since it is no longer classified as a planet (but a dwarf planet, TNO, KBO, plutoid, etc.) it is no longer in the running. Sorry, Pluto!



We've written many articles about Neptune here at Universe Today. Here's Who Discovered Neptune?, What is the Surface Temperature of Neptune?, What is the Surface of Neptune Like?, 10 Interesting Facts about Neptune, The Rings of Neptune, How Many Moons Does Neptune Have?



If you'd like more information on Neptune, take a look at Hubblesite's News Releases about Neptune, and here's a link to NASA's Solar System Exploration Guide to Neptune.



We've also recorded an entire episode of Astronomy Cast all about Neptune. Listen here, Episode 63: Neptune.

The post What is the Coldest Planet of Our Solar System? appeared first on Universe Today.

THE UNIVERSE - Life On Kepler-62f?

Life On Kepler-62f?:

A team of astronomers suggests that an exoplanet named 62f could be habitable. Kepler data suggests that 62f is likely a rocky planet, and could have oceans. The exoplanet is 40% larger than Earth and is 1200 light years away.



62f is part of a planetary system discovered by the Kepler mission in 2013. There are 5 planets in the system, and they orbit a star that is both cooler and smaller than our Sun. The target of this study, 62f, is the outermost of the planets in the system.



Kepler can't tell us if a planet is habitable or not. It can only tell us something about its potential habitability. The team, led by Aomawa Shields from the UCLS department of physics and astronomy, used different modeling methods to determine if 62f could be habitable, and the answer is, maybe.







According to the study, much of 62f's potential habitability revolves around the CO2 component of its atmosphere, if it indeed has an atmosphere. As a greenhouse gas, CO2 can have a significant effect on the temperature of a planet, and hence, a significant effect on its habitability.



Earth's atmosphere is only 0.04% carbon dioxide (and rising.) 62f would likely need to have much more CO2 than that if it were to support life. It would also require other atmospheric characteristics, .



The study modelled parameters for CO2 concentration, atmospheric density, and orbital characteristics. They simulated:

• An atmospheric thickness from the same as Earth's up to 12 times thicker.
• Carbon dioxide concentrations ranging from the same as Earth's up to 2500 times Earth's level.
• Multiple different orbital configurations.
  
  

It may look like the study casts its net pretty wide in order to declare a planet potentially habitable. But the simulations were pretty robust, and relied on more than a single, established modelling method to produce these results. With that in mind, the team found that there are multiple scenarios that could make 62f habitable.



“We found there are multiple atmospheric compositions that allow it to be warm enough to have surface liquid water,” said Shields, a University of California President’s Postdoctoral Program Fellow. “This makes it a strong candidate for a habitable planet.”









As mentioned earlier, CO2 concentration is a big part of it. According to Shields, the planet would need an atmospheric entirely composed of CO2, and an atmosphere five times as dense as Earth's to be habitable through its entire year. That means that there would be 2500 times more carbon dioxide than Earth has. This would work because the planet's orbit may take it far enough away from the star for water to freeze, but an atmosphere this dense and this high in CO2 would keep the planet warm.



But there are other conditions that would make 62f habitable, and these include the planet's orbital characteristics.



“But if it doesn’t have a mechanism to generate lots of carbon dioxide in its atmosphere to keep temperatures warm, and all it had was an Earth-like amount of carbon dioxide, certain orbital configurations could allow Kepler-62f’s surface temperatures to temporarily get above freezing during a portion of its year,” said Shields. “And this might help melt ice sheets formed at other times in the planet’s orbit.”



Shields and her team used multiple modelling methods to produce these results. The climate was modelled using the Community Climate System Model and the Laboratoire de Me´te´orologie Dynamique Generic model. The planet's orbital characteristics were modelled using HNBody. This study represents the first time that these modelling methods were combined, and this combined method can be used on other planets.



Shields said, "This will help us understand how likely certain planets are to be habitable over a wide range of factors, for which we don’t yet have data from telescopes. And it will allow us to generate a prioritized list of targets to follow up on more closely with the next generation of telescopes that can look for the atmospheric fingerprints of life on another world."



There are over 2300 confirmed exoplanets, and many more candidates yet to be confirmed. Only a handful of them have been confirmed as being in the habitable zone around their host star. Of course, we don't know if life can exist on other planets, even if they do reproduce the same kind of habitability that Earth has. We just have no way of knowing, yet.



That will change when instruments like the James Webb Space Telescope are able to peer into the atmospheres of exoplanets and tell us something about any bio-markers that might be present.



But until then, and until we actually visit another world with a probe of some design, we need to use modelling like the type employed in this study, to get us closer to answering the question of life on other worlds.











The post Life On Kepler-62f? appeared first on Universe Today.

MARS PLANET - How Long is a Year on Mars?

How Long is a Year on Mars?:

Mars and Earth have quite a few things in common. Both are terrestrial planets, both are located within the Sun's habitable zone, both have polar ice caps, similarly tilted axes, and similar variations in temperature. And according to some of the latest scientific data obtained by rovers and atmospheric probes, it is now known that Mars once had a dense atmosphere and was covered with warm, flowing water.



But when it comes to things like the length of a year, and the length of seasons, Mars and Earth are quite different. Compared to Earth, a year on Mars lasts almost twice as long - 686.98 Earth days. This is due to the fact that Mars is significantly farther from the Sun and its orbital period (the time it takes to orbit the Sun) is significantly greater than that of Earth's.

Orbital Period:

Mars average distance (semi-major axis) from the Sun is 227,939,200 km (141,634,852.46 mi) which is roughly one and half times the distance between the Earth and the Sun (1.52 AU). Compared to Earth, its orbit is also rather eccentric (0.0934 vs. 0.0167), ranging from 206.7 million km (128,437,425.435 mi; 1.3814 AU) at perihelion to 249.2 million km (154,845,701 mi; 1.666 AU) at aphelion. At this distance, and with an orbital speed of 24.077 km/s, Mars takes 686.971 Earth days, the equivalent of 1.88 Earth years, to complete a orbit around the Sun.







This eccentricity is one of the most pronounced in the Solar System, with only Mercury having a greater one (0.205). However, this wasn't always the case. Roughly 1.35 million years ago, Mars had an eccentricity of just 0.002, making its orbit nearly circular. It reached a minimum eccentricity of 0.079 some 19,000 years ago, and will peak at about 0.105 in about 24,000 years from now.



But for the last 35,000 years, the orbit of Mars has been getting slightly more eccentric because of the gravitational effects of the other planets. The closest distance between Earth and Mars will continue to mildly decrease for the next 25,000 years. And in about 1,000,000 years from now, its eccentricity will once again be close to what it is now – with an estimated eccentricity of 0.01.

Earth Days vs. Martian "Sols":

Whereas a year on Mars is significantly longer than a year on Earth, the difference between an day on Earth and a Martian day (aka. "Sol") is not significant. For starters, Mars takes 24 hours 37 minutes and 22 seconds to complete a single rotation on its axis (aka. a sidereal day), where Earth takes just slightly less (23 hours, 56 minutes and 4.1 seconds).



On the other hand, it takes 24 hours, 39 minutes, and 35 seconds for the Sun to appear in the same spot in the sky above Mars (aka. a solar day), compared to the 24 hour solar day we experience here on Earth. This means that, based on the length of a Martian day, a Martian year works out to 668.5991 Sols.

Seasonal Variations:

Mars also has a seasonal cycle that is similar to that of Earth's. This is due in part to the fact that Mars also has a tilted axis, which is inclined 25.19° to its orbital plane (compared to Earth's axial tilt of approx. 23.44°). It's also due to Mars orbital eccentricity, which means it will periodically receive less in the way of the Sun's radiance during at one time of the year than another. This change in distance causes significant variations in temperature.



While the planet’s average temperature is -46 °C (51 °F), this ranges from a low of -143 °C (-225.4 °F) during the winter at the poles to a high of 35 °C (95 °F) during summer and midday at the equator. This works out to a variation in average surface temperature that is quite similar to Earth’s – a difference of 178 °C (320.4 °F) versus 145.9 °C (262.5 °F). This high in temperatures is also what allows for liquid water to still flow (albeit intermittently) on the surface of Mars.



In addition, Mars' eccentricity means that it travels more slowly in its orbit when it is further from the Sun, and more quickly when it is closer (as stated in Kepler's Three Laws of Planetary Motion). Mars' aphelion coincides with Spring in its northern hemisphere, which makes it the longest season on the planet - lasting roughly 7 Earth months. Summer is second longest, lasting six months, while Fall and Winter last 5.3 and just over 4 months, respectively.







In the south, the length of the seasons is only slightly different. Mars is near perihelion when it is summer in the southern hemisphere and winter in the north, and near aphelion when it is winter in the southern hemisphere and summer in the north. As a result, the seasons in the southern hemisphere are more extreme and the seasons in the northern are milder. The summer temperatures in the south can be up to 30 K (30 °C; 54 °F) warmer than the equivalent summer temperatures in the north.

Weather Patterns:

These seasonal variations allow Mars to experience some extremes in weather. Most notably, Mars has the largest dust storms in the Solar System. These can vary from a storm over a small area to gigantic storms (thousands of km in diameter) that cover the entire planet and obscure the surface from view. They tend to occur when Mars is closest to the Sun, and have been shown to increase the global temperature.



The first mission to notice this was the Mariner 9 orbiter, which was the first spacecraft to orbit Mars in 1971, it sent pictures back to Earth of a world consumed in haze. The entire planet was covered by a dust storm so massive that only Olympus Mons, the giant Martian volcano that measures 24 km high, could be seen above the clouds. This storm lasted for a full month, and delayed Mariner 9‘s attempts to photograph the planet in detail.



And then on June 9th, 2001, the Hubble Space Telescope spotted a dust storm in the Hellas Basin on Mars. By July, the storm had died down, but then grew again to become the largest storm in 25 years. So big was the storm that amateur astronomers using small telescopes were able to see it from Earth. And the cloud raised the temperature of the frigid Martian atmosphere by a stunning 30° Celsius.



https://youtu.be/ZBZz0R6Ym5E



These storms tend to occur when Mars is closest to the Sun, and are the result of temperatures rising and triggering changes in the air and soil. As the soil dries, it becomes more easily picked up by air currents, which are caused by pressure changes due to increased heat. The dust storms cause temperatures to rise even further, leading to Mars' experiencing its own greenhouse effect.



Given the differences in seasons and day length, one is left to wonder if a standard Martian calendar could ever be developed. In truth, it could, but it would be a bit of a challenge. For one, a Martian calendar would have to account for Mars' peculiar astronomical cycles, and our own non-astronomical cycles like the 7-day week work with them.



Another consideration in designing a calendar is accounting for the fractional number of days in a year. Earth’s year is 365.24219 days long, and so calendar years contain either 365 or 366 days accordingly. Such a formula would need to be developed to account for the 668.5921-sol Martian year. All of this will certainly become an issue as human beings become more and more committed to exploring (and perhaps colonizing) the Red Planet.



We have written many interesting articles about Mars here at Universe Today. and How Long is a Year on Other Planets?, How Long is a Day on Mars?, How Long Does it Take Mars to Orbit the Sun?, Mars Compared to Earth, and Does Mars Have Seasons?



For more information, check out NASA's Solar System Exploration page on Mars.



Astronomy Cast also has several interesting episodes on the subject. Like Episode 52: Mars, and Episode 91: The Search for Water on Mars.

The post How Long is a Year on Mars? appeared first on Universe Today.

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ALIENS - Alien Minds I: Are Extraterrestrial Civilizations Likely to Evolve?

Alien Minds I: Are Extraterrestrial Civilizations Likely to Evolve?:

Is it likely that human level intelligence and technological civilization has evolved on other worlds? If so, what kinds of sensory and cognitive systems might extraterrestrials have? This was the subject of the workshop ‘The Intelligence of SETI: Cognition and Communication in Extraterrestrial Intelligence’ held in Puerto Rico on May 18, 2016. The conference was sponsored by the newly founded METI International (Messaging to ExtraTerrestrial Intelligence). One of the organization’s central goals is to build an interdisciplinary community of scholars concerned with designing interstellar messages that can be understood by non-human minds.





At present, the only clues we have to the nature of extraterrestrial minds and perception are those that can be garnered by a careful study of the evolution of mind and perception here on Earth. The workshop included nine speakers from universities in the United States and Sweden, specializing in biology, psychology, cognitive science, and linguistics. It had sessions on the evolution of cognition and the likely communicative and cognitive abilities of extraterrestrials.



Doug Vakoch, a psychologist and the founder and president of METI International, notes that astronomers and physicists properly concern themselves largely with the technologies needed to detect alien intelligence. However, finding and successfully communicating with aliens may require attention to the evolution and possible nature of alien intelligence. “The exciting thing about this workshop”, Vakoch writes, “is that the speakers are giving concrete guidelines about how to apply insights from basic research in biology and linguistics to constructing interstellar messages”. In this, the first installment dealing with the conference, we’ll focus on the question of whether the evolution of technological societies on other planets is likely to be common, or rare.



We now know that most stars have planets, and rocky planets similar to or somewhat larger than the Earth or Venus are commonplace. Within this abundant class of worlds, there are likely to be tens of billions with conditions suitable for sustaining liquid water on their surfaces in our galaxy. We don’t yet know how likely it is that life will arise on such worlds. But suppose, as many scientists suspect, that simple life is abundant. How likely is it that alien civilizations will appear; civilizations with which we could communicate and exchange ideas, and which could make their presence known to us by signaling into space? This was a central question explored at the conference.



In addressing such questions, scientists have two main sets of clues to draw on. The first comes from the study of the enormous diversity of behavior and nervous and sensory systems of the animal species that inhabit our Earth; an endeavor that has been called cognitive ecology. The second set of clues come from modern biology’s central principle; the theory of evolution. Evolutionary theory can provide scientific explanations of how and why various senses and cognitive systems have come to exist here on Earth, and can guide our expectations about what might exist elsewhere.



The basics of the electrochemical signalling that make animal nervous systems possible have deep evolutionary roots. Even plants and bacteria have electrochemical signalling systems that share some basic features with those in our brains. Conference presenter Dr. Anna Dornhaus studies how social insects make decisions collectively as an associate professor at the University of Arizona. She defines cognitive ability as the ability to solve problems with a nervous system, and sometimes also by social cooperation. An animal is more ‘intelligent’ if its problem solving abilities are more generalized. Defined this way, intelligence is widespread among animals. Skills traditionally thought to be the sole province of primates (monkeys and apes, including human beings) have now been shown to be surprisingly common.





For example, cognitive skills like social learning and teaching, generalizing from examples, using tools, recognizing individuals of one’s species, making plans, and understanding spatial relationships have all been shown to exist in arthropods (an animal group consisting of insects, spiders, and crustaceans). The evidence shows the surprising power of the diminutive brains of insects, and indicates that we know little of the relationship between brain size and cognitive ability.



But different animals often have different sets of cognitive skills, and if a species is good at one cognitive skill, that doesn’t necessarily mean it will be good at others. Human beings are special, not because we have some specific cognitive ability that other animals lack, but because we possess a wide range of cognitive abilities that are more exaggerated and highly developed than in other animals.







Although the Earth, as a planet, has existed for 4.6 billion years, complex animals with hard body parts don’t appear in the fossil record until 600 million years ago, and complex life didn’t appear on land until about 400 million years ago. Looking across the animal kingdom as a whole, three groups of animals, following separate evolutionary paths, have evolved especially complex nervous systems and behaviors. We’ve already mentioned arthropods, and the sophisticated behaviors mediated by their diminutive yet powerful brains.



Molluscs, a group of animals that includes slugs and shellfish, have also produced a group of brainy animals; the cephalopods. The cephalopods include octopuses, squids, and cuttlefish. The octopus has the most complex nervous system of any animal without a backbone. As the product of a different evolutionary path, the octopus’s sophisticated brain has a plan of organization that is completely alien to that of more familiar animals with backbones.



The third group to have produced sophisticated brains are the vertebrates; animals with backbones. They include fishes, amphibians, reptiles, birds, and mammals, including human beings. Although all vertebrate brains bear a family resemblance, complex brains have evolved from simpler brains many separate times along different paths of vertebrate evolution, and each such brain has its own unique characteristics.



Along one path, birds have evolved a sophisticated forebrain, and with it, a flexible and creative capacity to make and use tools, an ability to classify and categorize objects, and even a rudimentary understanding of numbers. Following a different path, and based on a different plan of forebrain organization, mammals have also evolved sophisticated intelligence. Three groups of mammals; elephants, cetaceans (a group of aquatic mammals including dophins, porpoises, and whales), and primates (monkeys and apes, including human beings) have evolved the most complex brains on Earth.



Given the evidence that intelligent problem solving skills of various sorts have evolved many times over, along many different evolutionary pathways, in an amazing range of animal groups, one might suspect that Dornhaus believes that human-style cognitive abilities and civilizations are widespread in the universe. In fact, she doesn’t. She thinks that humans with their exaggerated cognitive abilities and unique ability to use language to express complex and novel sorts of information are a quirky and unusual fluke of evolution, and might, for all we know, be wildly improbable. Her argument that alien civilizations probably aren’t widespread resembles one stated by the imminent and influential American evolutionary biologist Ernst Mayr in his 1988 book Towards a New Philosophy of Biology.



There are currently more than 10 million different species of animals on Earth. All but one have failed to evolve the human level of intelligence. This makes the chance of evolving human intelligence less than one in 10 million. Over the last six hundred million years since complex life has appeared on Earth, there have been tens of million different animal species, each existing for roughly 1-10 million years. But, so far as we know, only one of them, Homo sapiens, ever produced a technological society. The human lineage diverged from that of other great ape species about 8 million years ago, but we don’t see evidence of distinctly human innovation until about 50,000 years ago, which is, perhaps, another indication of its rarity.



Despite the apparent improbability of human level intelligence evolving in any one lineage, Earth, as a whole, with its vast array of evolutionary lineages, has nonetheless produced a technological civilization. But that still doesn’t tell us very much. For the present, Earth is the only habitable planet that we know much of anything about. And, since Earth produced us, we are working with a biased sample. So we can’t be at all confident that the presence of human civilization on Earth implies that similar civilizations are likely to occur elsewhere.



For all we know, the quirky set of events that produced human beings might be so wildly improbable that human civilization is unique in a hundred billion galaxies. But, we don’t know for sure that alien civilizations are wildly improbable either. Dornhaus freely concedes that neither she nor anybody has a good idea of just how improbable human intelligence might be, since the evolution of intelligence is still so poorly understood.



Most current evolutionary thinking, following in the footsteps of Mayr and others, holds that human civilization was not the inevitable product of a long-term evolutionary trend, but rather the quirky consequence of a particular and improbable set of evolutionary events. What sort of events might those have been, and just how improbable were they? Dornhaus supports a popular theory proposed by Dr. Geoffrey Miller, an evolutionary psychologist who is an associate professor in the Department of Psychology at the University of New Mexico and who also spoke at the METI institute workshop.



In our next installment we’ll explore Miller's theories in a bit more detail, and see why the abundance of extraterrestrial civilizations might depend on whether or not aliens think big brains are sexy.



For further reading:

Baluska, F. and Mancuso, S. (2009) Deep evolutionary origins of neurobiology. Communicative and Integrative Biology, 2:1, 60-65.



Chittka, L. and Niven, J. (2009) Are bigger brains better?, Current Biology. 19:21 p. R995-R1008.



Margonelli, L. (2014) Collective mind in the mound: How do termites build their huge structures. National Geographic.



Mayr, E. (1988) The probability of extraterrestrial intelligent life. In Towards a New Philosophy of Biology, Harvard University Press, Cambridge, MA.



Patton, P. E. (2015) Who speaks for Earth? The controversy over interstellar messaging. Universe Today.



P. Patton (2014) Communicating across the cosmos, Part 1: Shouting into the darkness, Part 2: Petabytes from the Stars, Part 3: Bridging the Vast Gulf, Part 4: Quest for a Rosetta Stone, Universe Today.



Tonn, S. (2015) Termites are teaching architects to design super-efficient skyscrapers. Wired Magazine.

The post Alien Minds I: Are Extraterrestrial Civilizations Likely to Evolve? appeared first on Universe Today.

MARS PLANET - Space Weather Causing Martian Atmospherics

Space Weather Causing Martian Atmospherics:

Strange plumes in Mars’ atmosphere first recorded by amateur astronomers four year ago have planetary scientists still scratching their heads. But new data from European Space Agency's orbiting Mars Express points to coronal mass ejections from the Sun as the culprit.







On two occasions in 2012 amateurs photographed cloud-like features rising to altitudes of over 155 miles (250 km) above the same region of Mars. By comparison, similar features seen in the past haven’t exceeded 62 miles (100 km). On March 20th of that year, the cloud developed in less than 10 hours, covered an area of up to 620 x 310 miles (1000 x 500 kilometers), and remained visible for around 10 days.



Back then astronomers hypothesized that ice crystals or even dust whirled high into the Martian atmosphere by seasonal winds might be the cause. However, the extreme altitude is far higher than where typical clouds of frozen carbon dioxide and water are thought to be able to form.



Indeed at those altitudes, we've entered Mars' ionosphere, a rarified region where what air there is has been ionized by solar radiation. At Earth, charged particles from the Sun follow the planet's global magnetic lines of force into the upper atmosphere to spark the aurora borealis. Might the strange features observed be Martian auroras linked to regions on the surface with stronger-than-usual magnetic fields?







Once upon a very long time ago, Mars may have had a global magnetic field generated by electrical currents in a liquid iron-nickel core much like the Earth’s does today. In the current era, the Red Planet has only residual fields centered over regions of magnetic rocks in its crust.







Instead of a single, planet-wide field that funnels particles from the Sun into the atmosphere to generate auroras, Mars is peppered with pockets of magnetism, each potentially capable of connecting with the wind of particles from the Sun to spark a modest display of the "northern lights." Auroras were first discovered on Mars in 2004 by the Mars Express orbiter, but they're faint compared to the plumes, which were too bright to be considered auroras.



Still, this was a step in the right direction. What was needed was some hard data of a possible Sun-Earth interaction which scientists ultimately found when they looked into plasma and solar wind measurements collected by Mars Express at the time. David Andrews of the Swedish Institute of Space Physics, lead author of a recent paper reporting the Mars Express results, found evidence for a large coronal mass ejection or CME from the Sun striking the martian atmosphere in the right place and at around the right time.







CMEs are enormous explosions of hot solar plasma — a soup of electrons and protons — entwined with magnetic fields that blast off the Sun and can touch off geomagnetic storms and auroras when they encounter the Earth and other planets.



"Our plasma observations tell us that there was a space weather event large enough to impact Mars and increase the escape of plasma from the planet’s atmosphere," said Andrews. Indeed, the plume was seen along the day–night boundary, over a region of known strong crustal magnetic fields.







But again, a Mars aurora wouldn't be expected to shine so brightly. That's why Andrews thinks that the CME prompted a disturbance in the ionosphere large enough to affect dust and ice grains below:



"One idea is that a fast-traveling CME causes a significant perturbation in the ionosphere resulting in dust and ice grains residing at high altitudes in the upper atmosphere being pushed around by the ionospheric plasma and magnetic fields, and then lofted to even higher altitudes by electrical charging," according to Andrews.







With enough dust and ice twinkling high above the planet's surface, it might be possible for observers on Earth to see the result as a wispy plume of light. Plumes appear to be rare on Mars as a search through the archives has revealed. The only other, seen by the Hubble Space Telescope in May 1997, occurred when a CME was hitting the Earth at the same time. Unfortunately, there's no information from Mars orbiters at the time about its effect on that planet.



Observers on Earth and orbiters zipping around the Red Planet continue to monitor Mars for recurrences. Scientists also plan to use the webcam on Mars Express for more frequent coverage. Like a dog with a bone, once scientists get a bite on a tasty mystery, they won't be letting go anytime soon.

The post Space Weather Causing Martian Atmospherics appeared first on Universe Today.

ALIENS - Finding Aliens May Be Even Easier Than Previously Thought

Finding Aliens May Be Even Easier Than Previously Thought:

Finding examples of intelligent life other than our own in the Universe is hard work. Between spending decades listening to space for signs of radio traffic - which is what the good people at the SETI Institute have been doing - and waiting for the day when it is possible to send spacecraft to neighboring star systems, there simply haven't been a lot of options for finding extra-terrestrials.



But in recent years, efforts have begun to simplify the search for intelligent life. Thanks to the efforts of groups like the Breakthrough Foundation, it may be possible in the coming years to send "nanoscraft" on interstellar voyages using laser-driven propulsion. But just as significant is the fact that developments like these may also make it easier for us to detect extra-terrestrials that are trying to find us.



Not long ago, Breakthrough Initiatives made headlines when they announced that luminaries like Stephen Hawking and Mark Zuckerberg were backing their plan to send a tiny spacecraft to Alpha Centauri. Known as Breakthrough Starshot, this plan involved a refrigerator-sized magnet being towed by a laser sail, which would be pushed by a ground-based laser array to speeds fast enough to reach Alpha Centauri in about 20 years.



https://youtu.be/_MCVaLMWQbA



In addition to offering a possible interstellar space mission that could reach another star in our lifetime, projects like this have the added benefit of letting us broadcast our presence to the rest of the Universe. Such is the argument put forward by Philip Lubin, a professor at the University of California, Santa Barbara, and the brains behind Starshot.



In a paper titled "The Search for Directed Intelligence" - which appeared recently in arXiv and will be published soon in REACH – Reviews in Human Space Exploration - Lubin explains how systems that are becoming technologically feasible on Earth could allow us to search for similar technology being used elsewhere. In this case, by alien civilizations. As Lubin shared with Universe Today via email:

"In our SETI paper we examine the implications of a civilization having directed energy systems like we are proposing for both our NASA and Starshot programs. In this sense the NASA (DE-STAR) and Starshot arrays represent what other civilizations may possess. In another way, the receive mode (Phased Array Telescope) may be useful to search and study nearby exoplanets."

DE-STAR, or the Directed Energy System for Targeting of Asteroids and exploRation, is another project being developed by scientists at UCSB. This proposed system will use lasers to target and deflect asteroids, comets, and other Near-Earth Objects (NEOs). Along with the Directed Energy Propulsion for Interstellar Exploration (DEEP-IN), a NASA-backed UCSB project that is based on Lubin's directed-energy concept, they represent some of the most ambitious directed-energy concepts currently being pursued.







Using these as a teplate, Lubin believes that other species in the Universe could be using this same kind of directed energy systems for the same purposes - i.e. propulsion, planetary defense, scanning, power beaming, and communications. And by using a rather modest search strategy, he and colleagues propose observing nearby star and planetary systems to see if there are any signs of civilizations that possess this technology.



This could take the form of "spill-over", where surveys are able to detect errant flashes of energy. Or they could be from an actual beacon, assuming the extra-terrestrials us DE to communicate. As is stated in the paper authored by Lubin and his colleagues:

"There are a number of reasons a civilization would use directed energy systems of the type discussed here. If other civilizations have an environment like we do they might use DE system for applications such as propulsion, planetary defense against “debris” such as asteroids and comets, illumination or scanning systems to survey their local environment, power beaming across large distances among many others. Surveys that are sensitive to these “utilitarian” applications are a natural byproduct of the “spill over” of these uses, though a systematic beacon would be much easier to detect."

According to Lubin, this represents a major departure from what projects like SETI have been doing for the past few decades. These efforts, which can be classified as "passive" were understandable in the past, owing to our limited means and the challenges in sending out messages ourselves. For one, the distances involved in interstellar communication are incredibly vast.

Even using directed-energy, which moves at the speed of light, it would still take a message over 4 years to the nearest star, 1000 years to reach the Kepler planets, and 2 million years to the nearest galaxy (Andromeda). So aside from the nearest stars, these time scales are far beyond a human lifetime; and by the time the message arrived, far better means would have evolved to communicate.



Second,  there is also the issue of the targets being in motion over the vast timescales involved. All stars have a transverse velocity relative to our line of sight, which means that any star system or planet targeted with a burst of laser communication would have moved by the time the beam arrived. So by adopting a pro-active approach, which involves looking for specific kinds of behavior, we could bolster our efforts to find intelligent life on distant exoplanets.

But of course, there are still many challenges that need to be overcome, not the least of which are technical. But more than that, there is also the fact that what we are looking for may not exist. As Lubin and his colleagues state in one section of the paper: "What is an assumption, of course, is that electromagnetic communications has any relevance on times scales that are millions of years and in particular that electromagnetic communications (which includes beacons) should have anything to do with wavelengths near human vision."

In other words, assuming that aliens are using technology similar to our own is potentially anthropocentric. However, when it comes to space exploration and finding other intelligent species, we have to work with what we have, and with what we know. And as it stands, humanity is the only example of a space-faring civilization known to us. As such, we can hardly be faulted for projecting ourselves out there.



Here's hoping ET is out there, and relies on energy beaming to get things done. And, fingers crossed, here's hoping they aren't too shy about being noticed!

Further Reading: arXiv

The post Finding Aliens May Be Even Easier Than Previously Thought appeared first on Universe Today.

PLUTO PLANET - Take A Virtual Reality Tour Of Pluto

Take A Virtual Reality Tour Of Pluto:

On July 14th, 2015, the New Horizons probe made history as it passed within 12,500 km (7,800 mi) of Pluto, thus making it the first spacecraft to explore the dwarf planet up close. And since this historic flyby, scientists and the astronomy enthusiasts here at Earth have been treated to an unending stream of breathtaking images and scientific discoveries about this distant world.



And thanks to the New York Times and the Universities Space Research Association's Lunar and Planetary Institute in Texas, it is now possible to take a virtual reality tour of Pluto. Using the data obtained by the New Horizon's instruments, users will be able to experience what it is like to explore the planet using their smartphone or computer, or in 3D using a VR headset.



The seven-minute film, titled "Seeking Pluto's Frigid Heart", which is narrated by science writer Dennis Overbye of the New York Times - shows viewers what it was like to approach the dwarf planet from the point of the view of the New Horizon's probe. Upon arrival, they are then able to explore Pluto's surface, taking in 360 degree views of its icy mountains, heart-shaped plains, and largest moon, Charon.



https://youtu.be/jIxQXGTl_mo



This represents the most detailed and clear look at Pluto to date. A few decades ago, the few maps of Pluto we had were the result of close observations that measured changes in the planet's total average brightness as it was eclipsed by its largest moon, Charon. Computer processing yielded brightness maps, which were very basic by modern standards.



In the early 2000s, images taken by the Hubble Space Telescope were processed in order to create a more comprehensive view. Though the images were rather undetailed, they offered a much higher resolution view than the previous maps, allowing certain features - like Pluto's large bright spots and the dwarf planet's polar regions - to be resolved for the first time.



However, with the arrival of the New Horizons mission, human beings have been finally treated to a close-up view of Pluto and its surface.  This included Pluto's now-famous heart-shaped plains, which were captured by the probe's Long Range Reconnaissance Imager (LORRI) while it was still several days away from making its closest approach.







This was then followed-up by very clear images of its surface features and atmosphere, which revealed floating ice hills, mountains and icy flow plains, and surface clouds composed of methane and tholins. From all of these images, we now know what the surface of this distant world looks like with precision. All of this has allowed scientists here at Earth to reconstruct, in stunning detail, what it would be like to travel to Pluto and stand on its surface.



Amazingly, only half of New Horizon's images and measurements have been processed so far. And with fresh data expected to arrive until this coming October, we can expect that scientists will be working hard for many years to analyze it all. One can only imagine what else they will learn about this mysterious world. And one can only hope that any news findings will be uploaded to the app (and those like it)!

The VR app can be downloaded at the New York Times VR website, and is available for both Android and Apple devices. It can also be viewed using headset's like Google Cardboard, a smartphone, and a modified version exists for computer browsers.

The post Take A Virtual Reality Tour Of Pluto appeared first on Universe Today.

SATURN PLANET - A Lord of Rings: Saturn at Opposition 2016

A Lord of Rings: Saturn at Opposition 2016:

They're back. After a wintertime largely devoid of evening worlds, the planets are once again in the evening sky. First Jupiter, then Mars have crossed opposition over the past few months, and now Saturn is set to take center stage later next week, reaching opposition at 7:00 Universal Time (UT) on the night of June 2/3^rd. This places the ringed world in a position of favorable evening viewing, rising in the east as the Sun sets in the west, and riding highest near local midnight across the meridian.



Opposition 2016 sees the planet Saturn looping through the southern realm of the constellation Ophiuchus, making a retrograde run this summer at the Scorpius border before looping back and resuming eastward motion. That's right: Saturn currently occupies the dreaded '13^th house,' of Ophiuchus, for all you Snake-Bearers out there. Saturn is currently at bright as it can be, at magnitude +0.04.







Saturn reaches opposition once every 378 days, as it orbits the Sun at a leisurely pace every 29.5 years. 2016 and the next few oppositions sees Saturn 'bottoming out,' sitting around -20 degrees south. Saturn won't peek northward across the celestial equator again until March 2026. This places the 2016 appearance of Saturn high in the sky south of the equator, transiting about 30 degrees above the southern horizon around midnight for folks observing around 40 degrees north latitude. Saturn also begins looping towards the star-rich region of the galactic equator for a crossing it late next year in December 2017. Saturn sits 9 Astronomical Units (AU) or 1.4 billion kilometers distant on June 3^rd, a slightly larger distance than usual, owing to the fact that the planet is headed towards aphelion on April 17^th, 2018.



The waxing gibbous Moon passes 3.2 degrees north from Saturn on Sunday, June 19^th, just a day before reaching Full.







Watch for a sudden brightening of the planet in early June, known as an 'opposition surge' due to what is known as the Seeliger effect. This is a coherent back-scattering of light, focusing it similar to highway retro-reflectors shining your headlights back at you at night. In this case, the Sun is the 'headlight,' and the millions of snowball moonlets hiding their shadows from view reaching 100% illumination are the highway retro-reflectors. The effect is subtle, to be sure, but serves to raise the brightness of the planet by about half a magnitude. This should be apparent in an animation sequence shot before, during and after over the span of a about a week. Any takers?







And speaking of the rings, here's another reason to check out Saturn this opposition 2016 season. The tilt of rings is about 26 degrees wide as seen from our Earthly perspective... about as wide as they can be. Saturn's rings were last edge on in 2009, and reach a maximum width of 27 degrees on October 16^th, 2017 before slowly heading towards edge on again in 2025.







At the eyepiece, Saturn shows a yellowish disk 18” extended to 43” across if you count the rings. Crank up the magnification to over 100x under good seeing, and the black thread of the Cassini division jumps into view. Saturn has 62 moons in all, with +9^th magnitude Titan being the brightest. You're looking at the most distant surface outpost of humanity, the site of the 2005 landing of the European Space Agency's Huygens lander. Six moons are readily visible in a small telescope, while the fainter moons Hyperion and Phoebe present a challenge to owners of extreme light buckets. Also, as Saturn heads past opposition and towards eastern quadrature 90 degrees from the Sun on September 2^nd, 2016, watch for the shadow of the bulk of the planet, cast back across the rings.







We never miss a chance to observe Saturn if it's above the horizon. Saturn is a sure-fire crowd-pleaser for any sidewalk astronomy session, and no one forgets their first glimpse of the glorious ringed world. You can just imagine how much consternation this bizarre-looking planet must have caused Galileo. You can tell just how primitive his first telescope was, as his sketches show off Saturn as more of a two-handled 'coffee cup' in appearance. Christaan Huygens first deduced something of the true nature of Saturn's rings in 1655, correctly claiming that they are physically separated from the disk.



Don't miss Saturn at opposition next week!

The post A Lord of Rings: Saturn at Opposition 2016 appeared first on Universe Today.

THE UNIVERSE - Milky Way Over the Spanish Peaks

Milky Way Over the Spanish Peaks:

Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.

2016 May 24

Milky Way Over the Spanish Peaks

Image Credit & Copyright: Martin Pugh; Rollover Annotation: Judy Schmidt


Explanation: That's not lightning, and it did not strike between those mountains. The diagonal band is actually the central band of our Milky Way Galaxy, while the twin peaks are actually called the Spanish Peaks -- but located in Colorado, USA. Although each Spanish peak is composed of a slightly different type of rock, both are approximately 25 million years old. This serene yet spirited image composite was meticulously created by merging a series of images all taken from the same location on one night and early last month. In the first series of exposures, the background sky was built up, with great detail being revealed in the Milky Way dust lanes as well as the large colorful region surrounding the star Rho Ophiuchus just right of center. One sky image, though, was taken using a fogging filter so that brighter stars would appear more spread out and so more prominent. As a bonus, the planets Mars and Saturn are placed right above peaks and make an orange triangle with the bright star Antares. Later that night, after the moonrise, the Moon itself naturally illuminated the snow covered mountain tops.

Tomorrow's picture: NGC 5078 and Friends

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STARRY NIGHT - NGC 5078 and Friends

NGC 5078 and Friends:

Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.

2016 May 25

Explanation: This sharp telescopic field of view holds two bright galaxies. Barred spiral NGC 5101 (top right) and nearly edge-on system NGC 5078 are separated on the sky by about 0.5 degrees or about the apparent width of a full moon. Found within the boundaries of the serpentine constellation Hydra, both are estimated to be around 90 million light-years away and similar in size to our own large Milky Way galaxy. In fact, if they both lie at the same distance their projected separation would be only 800,000 light-years or so. That's easily less than half the distance between the Milky Way and the Andromeda Galaxy. NGC 5078 is interacting with a smaller companion galaxy, cataloged as IC 879, seen just left of the larger galaxy's bright core. Even more distant background galaxies are scattered around the colorful field. Some are even visible right through the face-on disk of NGC 5101. But the prominent spiky stars are in the foreground, well within our own Milky Way.

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