Your Astronomy Now

At certain times of the year and dependent upon where you live, hopefully you can be outside to enjoy the beautiful days as well as glorious night sky.

After the long winter months, there will be plenty of opportunities to explore our outside world in relative comfort. When we look to the skies, most of us are amazed at its splendor but don’t have a clue as to what we are looking for or at. So, when the weather permits, step outside and share in the expanse of the sky.

As parent and child begin their journey of the solar system, remember, it is suppose to be fun. There are so many stars in the sky that you might want to start simple and build your way. Astronomy for kids does not need to be confusing or intimidating. It can simply be fun and bonding!

Although the night sky is well mapped and extremely fascinating, it is also complex. To spark long-remembered conversations and moments to be shared, start with a few simple searches for planets that are visible to the naked-eye: Mercury, Venus, Mars, Jupiter, and Saturn.

Mercury is the closest planet to the sun. The best opportunity to observe Mercury is when it is at its highest point in the sky. Sometimes Mercury is visible in the evening. In this case you can start observing Mercury shortly after sunset but you will have less than an hour until the planet sets below the horizon. At other times Mercury is visible in the morning. You will be able to see Mercury at most an hour or so before sunrise and can observe it until the light from the rising sun drowns it out.

Venus is the second closest planet to the sun. Whenever Venus is visible, it is much brighter than anything in the sky, with the exception of the sun and moon.

Mars is the fourth closest planet to the sun. When Mars is bright, it is bright red; when it is dim, it is a pale pink (at such times it may be difficult to see any color at all). Mars goes from bright to dim back to bright every two years.

Jupiter is the fifth closest planet to the sun. Jupiter is the largest planet in the Solar System. Jupiter is lost in the Sun’s glare. Nevertheless, it is out there, on the other side of the Sun from Earth and 580 million miles away from our planet. It returns to view in mid-January, low in the morning sky.

Saturn is the sixth planet from the sun. Saturn appears pale yellow to the naked eye. Although never appearing quite as bright as the other planets, it is still obvious when the position is found.

Mercury, Mars, Jupiter and Saturn are brighter than anything other than Venus, the sun or moon, Sirius and Canopus.

Once you have found, identified and possibly mapped the obvious, search deeper. You may find that you are enjoying the night sky as much as your child!

Solar system diagrams help readers visualize the actual positions of the planets in the solar system. They provide an easy understanding of our earth and the solar system.

The orbit diagrams of the solar system show the planes of the earth and the comets. Comet orbit diagrams show the comets’ relative movement with the sun. There are two types of orbit diagrams - outer solar system orbit diagrams and inner solar system orbit diagrams.

Outer solar system orbit diagrams show the positions of all asteroids and comets with semi-major axes. They also show orbits and positions of planets such as Earth, Jupiter, Saturn, Uranus, Neptune, Pluto, and comets like Halley and Hale-Bopp. In outer solar system orbit diagrams, asteroids and comets are shown in separate colors or blocks.

The inner solar system diagrams show the positions of all numbered asteroids and all numbered comets. The positions and orbits of the planets Mercury, Venus, Earth, Mars, and Jupiter are also shown. In the diagram, asteroids and comets are represented in separate blocks or colors. Top diagrams and bottom diagrams of the inner solar system can also be plotted. The inner solar system diagram shows the location of the asteroid belt and the distribution of interplanetary dust.

Separate comet and asteroid orbit diagrams can be viewed using a java based orbit applet. The distribution of orbital elements for most known inner solar system asteroids and comets are shown using distribution diagrams such as distribution diagram of elements for comets and asteroids, distribution diagram of elements for asteroids only, and distribution diagram of semi major axis. Bifurcation diagrams show selected stable and unstable orbits and the numerical iterations depending on a parameter.

The Phoenix Mars Polar Lander is slated to land on Mars’ north pole on May 25th - very soon now! Phoenix is intended to look for signs of microbial life, and there’s a case that evidence may be found on Mars.

The first piece of evidence is purported microfossils found in an Antarctic meteorite in 1997 - this Shergottic meteorite ALH84001, estimated to be 4.5 billion years old, is still the subject of some controversy. There are some who say that the microstructures are evidence of biotic contamination from its long tenure on Earth, others maintain hope that it’s evidence of a link to life on the Mars.

Martian life has a long held a fascination for astronomers - for one, it’s a bright object in the sky, and for two, after the development of the telescope in the 1600s, it showed the most obvious color changes of any object in the sky. From Schiapiarelli to Lowell to Wells, the prospect of Martian life has held the imagination, even as the scientific evidence mounted that such life would be nothing at all like we’d expect.

The case for life on Mars is reinforced by the exposure of bacteria on Lunar missions - samples went out, and came back, and were able to survive the harsh Solar and Van Allen radiation belts - even some of the plasma and thermal changes of reentry through the Earth’s atmosphere. So life is remarkably hardy and capable of surviving in the vicious environment of space. Achaeobacteria and tube worms living on volcanic vents show that life can survive and thrive wherever there’s a source of energy to exploit, even down in the depths of the ocean where sunlight isn’t even a memory.

However, the question of life on Mars has a few more complications. For one, it’s a cold case -whether there was life in the past, Mars’ surface conditions have changed over the last 5 billion years. There are definite epochs in Martian geology (called areology), where Mars speculation shows Mars having a thicker atmosphere than now, and receding (and advancing) surface water levels. Mars’ current climate cannot support liquid water on the surface - the temperature is too low, and the atmospheric pressure is too low; if you took a tray of ice cubes out on the surface, they’d slowly evaporate by sublimation, the way dry ice does on Earth.

What caused these changes in Martian climate? Plate tectonics, or rather, the lack of them. Earth’s biosphere is driven in large part by plate tectonics, which serve to bury carbon (in the form of limestone) caused by sedimentation. The driving force on plate tectonics is the decay of radioactive elements in the Earth’s core.

Venus also shows evidence of having had plate tectonics in the past; its plate tectonics appear to have stopped due to the lack of water in the subsurface crust - the water in the oceans is far from being the majority of it on the planet; most of the rest is seepage down into the Earth’s mantle, where it acts as a lubricant.

On Mars, due to short range radio surveys by the Mars Reconnaissance Orbiter, we now show that Mars’ crust isn’t as flexible as Earth’s - it’s not being pressed down as much as it should be by the mass of the Martian polar ice cap. This is indicative that Mars is tectonically dormant.

Why does tectonic dormancy matter for the case for life on Mars? Tectonic activity is the likely driving energy source for any Martian microbes out there, and it’s the only candidate presently known to make long standing seeps of liquid water, which is necessary for life as we know it.

Phoenix will be landing at the Martian north pole to give us some answers - but even if it finds nothing, there’s no reason to give up hope. Mars has a surface area equal to all of Earth’s dry land put together. Phoenix will only be able to sample an area comparable to a ring of soil around an office cubical.

Phoenix’ other mission profile is to give climate data on Martian weather patterns and observational data on the polar winter, and it’s slated to provide data for at least six months, with optional extensions for years. (The Spirit and Opportunity rovers are now approaching the fourth anniversary of the beginning of their 90 day survey…)

Phoenix live commentary from NASA begins at at 3:30 pm USA Pacific time on the 25th as the craft prepares for its decent into the martian atmosphere, or about 9:30 on the morning of the 26th for Eastern Australia.