PHOBOS AND DEIMOS – MARTIAN MOONS 

There are two small asteroid-like moons that orbit Mars: Phobos and Deimos. Both are named after ancient Greek gods. The larger moon, Phobos, passes across the Martian sky from west to east three times in one Martian day (one sol). On Mars it would appear as half the size of a full moon on Earth. It is so close to the surface that it would not be visible from the Martian poles.

Deimos orbits at about 12,470 miles from the planet and moves slowly from east to west. This moon takes about 30 hours, a little over one Martian sol, to orbit its host. Because of its distance from the planet and the fact that it is only 8 miles across, it appears as a small dot of light in the sky, more like a star than a moon. The surface of this moon is covered with a layer of powdery dust that could be several hundred feet deep. Only the tips of giant boulders can be seen peeking above the dust. Scientists believe the dust formed as a result of billions of years of meteorite impacts. 

Phobos is the larger of the two moons at 14 miles across, and it orbits Mars from only 3,700 miles from the surface of the planet. Phobos is interesting because of its grooves and distinctive crater. It is believed that Phobos survived a powerful impact that may have fractured its interior. The impact may also be responsible for a series of long, deep grooves that appear to radiate away from the crater to an oddly shaped area on the other side of the moon. This impact gouged a large crater which has been named the Stickney crater. Asaph Hall discovered the moons in 1877. He named the crater on Phobos “Stickney,” his wife’s maiden name. He said if it were not for her encouragement he would have given up his search for the Martian moons.

Scientists can only speculate if these moons were born of Mars itself or if they are captured meteors, though the more popular belief is the latter. Much like our Earth moon, both Martian moons always face the same side to the planet. Both moons were named after the sons of Aries, the Greek god to Mars. Phobos means “fear” and Deimos means “dread.” Deimos seems to be slowly spiraling away from the planet while Phobos is drawing closer, which may cause it to collide with the planet in about 50 million years.

I’m wondering: Will Deimos disintegrate and form a ring around Mars before it would collide? Scientists believe there may be water on Phobos; if so, will we create a base on Phobos to store supplies? What do you think will happen?

Visit this link for images of Phobos and Deimos:

http://solarsystem.nasa.gov/planets/profile.cfm?Object=Mars&Display=Sats

My resources are: NASA, Starry Skies, Universe Today, and Space.com

Discover my Lill and Mewe series books about Mars on my website: www.authorjeanelane.com

OORT CLOUD - IS THIS REALLY A CLOUD?     

The Oort Cloud is not really a cloud at all but if we could ‘see’ it from a distance it may have that appearance. It has yet to be observed, the Oort Cloud is a spherical collection of icy objects presumed to exist in the far reaches of the Solar System. It was first suggested by Jan Hendrik Oort in 1950, after his observations of comets. He concluded that comets had the following things in common:

·        Their orbits indicated that they did not originate in interstellar space.

·        They come from all directions – there is no single orbit.

·         Their aphelia (farthest point) tended to group at about 50,000AU (the sun is 1AU from Earth).

Taking all of these observations into consideration and the frequency that they occurred, Oort decided that billions of potential comet material must exist in a spherical shell surrounding the Solar System. Then given their distance from the sun and the weaker gravitational pull, disturbances from objects outside the Solar System could ‘knock’ these icy objects into plunging orbits around the Sun. This would result in the comets we observe.

The Oort Cloud is still generally acknowledged as the origin of the long-period comets, whereas the short-period comets originate from the Kuiper Belt. The Oort Cloud is thought to be an extension of the Kuiper Belt only much larger, containing billions of objects and maybe trillions of small icy objects. Scientists believe that during the planetary formation these objects were left-over debris. They were caught and flung out to the edge of the Solar System by the gravitational pull of Jupiter and Saturn, acting like a sling shot.

Two of the most famous comets, Halley and Swift-Tuttle, possibly higher orbit comets are ones that were pulled into shorter period orbits by the planets. Long period comets, such as Hyakutake and Hale-Bopp can appear at any time and come from any direction, but these two bright comets can usually be seen every 5 to 10 years.

We still have much to learn about the Oort Cloud. To date, scientists believe this region may contain the existence of two Oort Clouds, the inner and the outer clouds. They believe that the objects that reside there formed closer to the sun and were scattered to the outer regions due to gravitational effects. The last theory most commonly accepted is that the Oort Cloud defines the outer most region of our Solar System under the influence of the gravitational pull of our sun.

Let’s take a look – Images and a video:

http://www.space.com/16401-oort-cloud-the-outer-solar-system-s-icy-shell.html

 

My sources: Kids Astronomy, Wikipedia, Solarviews.com, Space.com, European Space Agency, Astronomy/Cosmos, and Universe Today.

THE KUIPER BELT…Where is it?

The Kuiper Belt is a disc-shaped region of icy objects located beyond the orbit of Neptune.  The region was named after a Dutch astronomer, Gerard Kuiper, in 1992. Scientists believe this area is far larger than the rocky asteroid belt that lies between Mars and Jupiter. It is believed this region is 20 to 200 times the size of the Asteroid Belt.

Some known facts about the Kuiper Belt are:

·         The known icy worlds and comets in this region are much smaller than our moon.

·         The Kuiper Belt is a donut shaped ring extending just beyond the orbit of Neptune from about 30 to 55 AU (Astronomical Unit).  The distance from our sun to Earth is 1 AU, or 93 million miles.

·         Short period comets that take less than 200 years to orbit the sun, originate in this region. Long period comets that take more than 200 years, originate in the Oort Cloud, which lies just beyond the Kuiper Belt.

·         There may be hundreds of thousands of icy objects over 62 miles in diameter within the Kuiper Belt.

·         There have been eight identified dwarf planets orbiting within the Kuiper Belt and several of these have tiny moons.

·         The first mission to the Kuiper Belt is New Horizons. New Horizons will reach Pluto in 2015.

·         Gerard Kuiper predicted the existence of such a region in space during the 1950’s. It wasn’t until 1992 his theory was proven correct

Detecting objects in this region of space is not easy because they are very faint and move very slowly. It takes hundreds of years for one of these objects to complete one orbit around the sun.

Later, we have come to realize that Pluto and its five known moons: Charon, Hydra, Nix, P4, discovered by Hubble in 2011, and P5 more recently discovered by Hubble in 2012, reside in the Kuiper Belt.  Pluto isn’t the only dwarf planet to take up residence there, Eris, Makemake, Haumea, Quaoar, Sedna, Orcus, and Varuna orbit in the icy fringes of our solar system.   

The Kuiper Belt is still a busy place. There have been over a thousand objects discovered and it’s theorized that there are as many as one-hundred thousand objects larger than 62 miles in diameter yet to be discovered there.

NASA’s New Horizons spacecraft will reach this region in 2015, and capture the first ever close up pictures of a KuiperBelt object, images of the surface of Pluto.

For more information – check this site out:

New Horizons – now in flight:  http://solarsystem.nasa.gov/missions/profile.cfm?MCode=PKB

My sources: NASA, Windows to the Universe, Wikipedia, Universe Today, and European Space Agency

The Drake Equation

The Drake Equation: The Search for ET

N = R* f_p n_e f_l f_i f_c L   So what the heck is this anyway?  So glad you asked. It’s quite an intriguing formula and has to do with the probability of life existing somewhere “out there.”  In 1961, while working as a radio astronomer at the National Radio Astronomy Observatory in Green Bank, West Virginia Dr. Frank Drake established a scientific formula which became known as the “Drake Equation.” It was actually in 1960 that Drake began his personal search for extraterrestrial intelligence which, shortly afterwards, led to his establishing the SETI institute.

It’s an awesome concept which was put into an equation over 50 years ago. Although Drake made some assumptions to arrive at his equation, you must admit, it’s a great way to help us organize our thinking in the way we search for extraterrestrial life. In 1960 his search was called Project Ozma. As Drake said, “For all we knew, practically every star in the sky had a civilization that’s transmitting.” What he found was that every star is not home to an intelligent, communicative civilization. But even Carl Sagan said that SETI as a science should be pursued.

As we have learned over time, there are many variables with Drake’s formula. The first three quantities are ones we can observe with our current technology. It’s the last four terms where the math gets a little fuzzy. We can say that life is ‘possible’ but not that it actually exists. Scientists today are much more conservative with their estimate and some won’t even speculate. If there is life, what percent of that is intelligent enough to communicate with us? Drake’s answer was 1%. Even that was a guesstimate. Of that 1% what are the chances that it would communicate on a level we could understand?

This may all change, because today we are searching for exoplanets that resemble Earth in size and temperature. Transiting Exoplanet Satellite Survey (TESS) and the James Webb Space Telescope are both due to launch around 2018. They will be looking for Earth-like planets orbiting small stars. Their mission is to concentrate on atmosphere, gases, oxygen, water vapor or other gases that do not belong to ‘dead’ worlds. Sara Seager has revised the Drake equation to focus simply on the presence of any alien life. Her focus is on M stars, the most common. Her calculation suggested that two inhabited planets could be discovered during the next decade. 

N = N*F_QF_HZF_OF_LF_S  This is the Sara Seager equation, a bit different than Drake’s original.
As for me, well I hope that we do find some fascinating, intelligent, and above all, friendly aliens that would be tolerant of us.

For more information on this topic, please visit:

Drake Equation:    http://www.pbs.org/lifebeyondearth/listening/drake.html

Sara Seager:          http://www.centauri-dreams.org/?p=28976

My sources: www.astrociets,org/edu, www.space.com, www.astrobioloblog.wordpress.com

THE HELIOSPHERE

THE HELIOSPHERE

The region of space governed by the Sun is called the heliosphere. This area is filled with plasma from the Sun in the form of the solar wind. Beyond the heliosphere, interstellar space exists, and it is filled with plasma from other stars. The heliosphere marks the division between the solar plasma and the interstellar plasma. It is the area where the pressure of the solar wind equals the pressure of the interstellar medium.

I understand that all this is hard to picture in your mind, but try to imagine the heliosphere as a kind of bubble that contains the solar system. It's a magnetic sphere that reaches beyond Pluto and is caused by the solar winds.

NASA's Cassini spacecraft suggests that the heliosphere may not possess the comet-like shape that scientists thought, but instead is more like a big, round bubble. This changes what they have thought for the past fifty years. The images indicate that the solar wind's interaction with the interstellar medium is instead more significantly controlled by particle pressure and the energy density of the magnetic field.

The Voyager spacecraft(s) have crossed the termination shock several time as it moves in and out from the Sun. This is due partly because of the pressure of the solar wind, which can increase or decrease as it flows from the Sun. Before reaching the heliosphere the solar wind is slowed from supersonic to subsonic speed, and this creates a shockwave called the termination shock.

So all this makes me wonder, when we have one, can our spacecraft travel safely beyond the heliosphere and withstand the termination shock? Can we protect the lives of the people inside? Of course, this means we are leaving our solar system. This is something to think about, one more thing to consider in space travel.

More information at http://www.universetoday.com/32519/heliosphere/

references: www.universetoday.com, www.cosmos4kids.com/files/solsyst2, http://helios.gsfc.nasa.gov/heliosph.html, www.sciencedaily.com/releases/2009/10/091016101807.htm

Finding Earth-like Planets

Astronomers are actively searching for Earth-like planets outside of our solar system - or as they say, exoplanets. Most of the planets they have found so far are enormous, at least the size of Jupiter. It's much more difficult to find planets as small as Earth. Now, scientists believe that 6 percent of red dwarf stars have Earth-sized planets located at the right distance from the star to be potentially habitable.

Our Milky Way Galaxy may be home to approximately two billion Earth-like planets. This is based on a new study and initial data from NASA's Kepler space telescope. Based on Kepler's findings so far, the studies are up to 2.7 percent of all sun like stars in the Milky Way host so-called Earth like worlds. As of this February, Kepler has confirmed 15 new planets and found an additional 1,235 planet candidates, including a small planet outside of our solar system. Kepler will collect data for a minimum of three and a half years and plans to undertake a more complete census at a later date.

What I have found in my research is that the closest Earth-like planet astronomers have reported may be only 13 light years away - or approximately 77 trillion miles. They have not identified it yet, but feel it should be there based on the teams' study of red dwarf stars. Most of us have heard of Gilese 581, a red dwarf star in the constellation Libra that lies about 20.5 light years from Earth. The European Southern Observatory (ESO) telescope in Chile has discovered Gilese 581d, a planet they speculate to have a rocky core, an icy layer, and a liquid ocean at the surface with an atmosphere. At this stage they can only speculate but it is possible. Gilese 581e is another planet looking much like Earth, except that it is very hot because it so close to its host star.

NASA and the scientists working on this project favor Kepler-22b which was discovered about 600 light years from us, in another solar system. They view this planet as having the best chances of life because of the striking similarities to Earth. Its surface is a comfortable 72F and the star it orbits can almost be a twin of our sun. Although it is 2.4 times bigger than Earth, scientists suspect it probably has water and land making it a great target for life. Now scientists have found other planets in in the Kepler-22 group which makes this a study of 3 or 4 planets that may all be Earth-like. 

So how do scientists find these planets? That's a great question -  there are four ways:
The first is called the "radial velocity method": This is when stars are pulled back and forth by the gravitational pull of the planet. This allows them to measure the shift in the light frequency.
Another method is "positional astronomy": This is when they take a measurement of the tiny shift in a star's location on the sky which is caused by the gravitational pull of a planet. They can determine mass and orbit as well.
The "transit method": Scientists have found that a planet blocks out a small portion of the star's light when it passes directly between a star and the observer. They will watch it to confirm the fluctuations in the star's light. This means a planet is orbiting that star.
Last is the "gravitational microlensing" method: This comes from Einstein's thoughts regarding his theory of relativity. I like this ~ gravity bends space. The planet's gravity will  act like a lens  for a short time to focus light from a star. This works well with more distant stars. It seems to warp space to cause a noticeable increase in brightness and a change in position of the star.

I never said it's easy to find planets outside of our solar system. Most of them are very far away, but recently astronomers have found a planet that orbits a star called Alpha Centauri B, which is our closest star about 4 light years away or 23.5 trillion miles. It is a rocky planet but may be too hot to sustain life. Any time we can measure the distance in space using miles (even if it is trillions) this would be termed as being in our neighborhood.

There's a plan to search in more depth for Earth-like planets:  http://www.dailygalaxy.com/my_weblog/2013/04/kepler-mission-20-to-launch-in-2017-thousands-of-neigboring-earth-like-alien-planets-to-be-identifie.html

My references include: NASA online, Daily Planet, StarDate.org, and dailygalaxy.com.

WHAT IS CURIOSITY UP TO NOW?

Since its landing at the Gale Crater, Mars, Curiosity is now trekking westward from Glenelg to Yellowknife Bay and Point Lake. Did you know that the rover team is on Martian time? They are tracking Curiosity for 24 hours, 39 minutes, and 35 seconds per sol (day), and this will last for one Martian year or 687 sols. Mars gets chilly, the temperature is about -130F degrees, and windy with wind gusts to 90mph. Oh and the rover only covers a distance of about 300 ft in a day.

 In retrospect, the science team decided to name the exact landing spot “Bradbury Landing.” Glenelg was chosen because it’s a site that appears to contain three different rock types. Of interest is the sedimentary rock that we all know is formed by materials deposited by flowing water. What is indicated by the other various colors of rock in that area is yet unknown. It seems that what we do know is that Mars had an environment that was able to support water on its surface in the past.

As a matter of fact I came across this statement, “We have found a habitable environment that is so benign and supportive of life that probably, if this water was around and you had been on the planet, you would have been able to drink it,” said John Grotzinger of Caltech in Pasadena.

It has also been confirmed that the rock drilling results reveal elements found on Earth and clay containing not much salt which would indicate a lake may have existed there before.  Remember, the reason for this mission is to “search for organic life on Mars,” over a two year period.

Well, looks like we’ve determined time again that water did exist on Mars. Don’t get me wrong, that’s great news. But what else may have existed on Mars? Any life forms, no matter how small, are they like any life form on Earth? Perhaps they are completely alien. Now that would be something for discussion.

But how about this news – radiation levels on Mars now are comparable to that of the same levels the astronauts are experiencing on the International Space Station. What this means is that longer term surface exploration is possible, outside the possibility of solar eruptions or surface sandstorms.

This gives us all something to think about over the next decade.  Personally, bar any yet unknown factors that would kill a manned-mission there, I think scientists are planning a visit if not colonization. We need to focus on that warp speed theory, so we can get to Mars in minutes, not several months or years. There is still a lot of work to be done. 

You can check NASA’s map of Mars for the current location of Curiosity here:

http://mars.jpl.nasa.gov/msl/mission/whereistherovernow/

References: NASA, Universe Today, and Space.com