Last year, the brightest object ever seen in the universe was detected. This was a gamma-ray burst (or GRB, in astronomers’ usual lingo) 7.5 billion light-years away, which means that the light we saw was emitted 7.5 billion years ago, more than half of the universe’s current age of 13.7 billion years.

Last week, the orbiting Swift Observatory topped that discovery with the detection of a gamma-ray burst that is 13 billion light-years away!  The source of the burst is likely a supernova, the explosion of a star much more massive than our Sun.  Known as Population III stars, these were the earliest stars to form in our universe, and produced the seeds of later star formation, generating chemical elements like iron, calcium, oxygen, and so forth—that are essential for life on Earth.  So as far removed from daily life as this gamma-ray burst might seem, it is because such huge, early stars existed and exploded in such a violent way that we are here today.

Posted by Matthew R. Francis under Director's Notes & Science Ideas & Science News | No Comments »

2009 is the International Year of Astronomy!

From the International year of Astronomy website:

The International Year of Astronomy 2009 is a global effort initiated by the International Astronomical Union and UNESCO to help the citizens of the world rediscover their place in the Universe through the day- and night-time sky, and thereby engage a personal sense of wonder and discovery.

Please join us in making 2009 a great year for the M. D. Anderson Planetarium!

Posted by Matthew R. Francis under Planetarium News & Public Events & Science News | No Comments »

Earth obviously has life.  But, if we were looking at the Earth from outside the Solar System, could we detect it with current technology?  Likewise, if there is life on Mars, or Titan, or Enceladus, or wherever, is our equipment good enough to find it?

A recent article on Astronomy.com discusses using the Venus Express probe to study Earth. Since Venus Express is orbiting Venus, Earth appears in its instruments as a featureless dot, but the probe can try to identify the chemicals on Earth indicating life’s presence. This is similar to earlier missions to the Atacama Desert in Chile, which attempted to find microbes in the soil using technology similar to that of the Mars Rovers.

You might think that finding life is pretty easy, but experiments such as these show it isn’t quite so simple. Robotic probes tend to look for chemical tracers, since those are easy things to look for. However, life itself is more than just its chemicals, so it remains to be seen if missions like the Phoenix Mars lander will find life. In other words, if life exists on Mars, will the instruments on Phoenix be good enough to find it?

Speaking of Mars, on Monday, October 20, we present a revised and improved version of Water on Mars, Life on Mars.  On July 31, 2008, the Phoenix Mars Mission team announced the first direct evidence for water on the desert planet Mars. In this special presentation, we will take a look at Mars, what we know about it, and what we hope to learn in the future. We will see

• how Mars is similar to Earth, and how it is very different;
• why water is so important to Earth, and what it might mean for Mars;
• what finding water on Mars means about the possibility of life on Mars;
• and other exciting topics!

I hope you can join us on October 20 at 7:30 PM.  As always, admission is $5 per adult, $3 per child under 18, and $10 for a family of 3 or more. Lambuth students, faculty, and staff are admitted free with their ID.

Posted by Matthew R. Francis under Director's Notes & Science Ideas & Science News | No Comments »

Can you keep track of the dwarf planets? Here is the official list, as of last week:

• Ceres, which is the smallest dwarf planet and the only one so far designed from the Asteroid Belt
• Pluto, the most famous dwarf planet, and one that has created the strongest emotions in people
• Eris, the largest dwarf planet, and the one that inspired astronomers to create the dwarf planet category
• Makemake, which I wrote about this summer
• Haumea, designated as a dwarf planet last week

Haumea is really odd compared to the others:  it isn’t spherical.  (Technically, it’s ellipsoidal.)  Along its longest axis, it is larger than Pluto, so its total volume is comparable to that of Pluto.  What does this mean for the definition of dwarf planet we discussed earlier?  Stay tuned….

Posted by Matthew R. Francis under Science News | No Comments »

On July 31, 2008, the Phoenix Mars Mission team announced the first direct evidence for water on the desert planet Mars. In this special presentation, we will take a look at Mars, what we know about it, and what we hope to learn in the future. We will see

• how Mars is similar to Earth, and how it is very different;
• why water is so important to Earth, and what it might mean for Mars;
• what finding water on Mars means about the possibility of life on Mars;
• and other exciting topics!

I hope you can join us on September 22 at 7:30 PM.  As always, admission is $5 per adult, $3 per child under 18, and $10 for a family of 3 or more. Lambuth students, faculty, and staff are admitted free with their ID.

Posted by Matthew R. Francis under Director's Notes & Public Events & Science News | 1 Comment »

How many planets do we know about?  Are there eight?  Nine?  Eleven?

The answer:  more than  300, but almost all of these are found orbiting stars other than our Sun.  In less than 20 years, astronomers have discovered large numbers of planets orbiting other stars, which are known as extrasolar planets or exoplanets.  So, for the first time in history, our Solar System is no longer our only source of information about planets.  We can’t assume that our Solar System and its planets are typical of every planetary system in the galaxy any longer.  Most of the planets we have found are very large (many are more massive than Jupiter), and a large number have been discovered closer to the host stars than Mercury.

Continue Reading »

Posted by Matthew R. Francis under Science News | No Comments »

On Monday, September 22, the M. D. Anderson Planetarium presents….

Water on Mars, Life on Mars

On July 31, 2008, the Phoenix Mars Mission team announced the first direct evidence for water on the desert planet Mars. In this special presentation, we will take a look at Mars, what we know about it, and what we hope to learn in the future. We will see

• how Mars is similar to Earth, and how it is very different;
• why water is so important to Earth, and what it might mean for Mars;
• what finding water on Mars means about the possibility of life on Mars;
• and other exciting topics!

I hope you can join us on September 22 at 7:30 PM.  As always, admission is $5 per adult, $3 per child under 18, and $10 for a family of 3 or more. Lambuth students, faculty, and staff are admitted free with their ID.

Posted by Matthew R. Francis under Public Events & Science Ideas & Science News | No Comments »

This Wednesday (September 10), the world’s most powerful high-energy physics experiment will begin operation.  The Large Hadron Collider (or LHC), part of the European international experimental facility CERN, is one of the most anticipated projects in all of physics for many years.

So what does the LHC have to do with astronomy?  Why is your intrepid planetarium director excited about this, when it doesn’t seem to have any relation to the usual stuff we talk about in the planetarium?  The answer lies in the mysterious substance known as dark matter, which comprises more than 20% of the contents of our universe.  In contrast, ordinary matter—atoms and molecules, which is the stuff of our bodies and our planet—only makes up about 4% of the contents of the universe.  (The rest is an even more mysterious substance known as dark energy, a subject best left for another essay!) Continue Reading »

Posted by Matthew R. Francis under Science Ideas & Science News | No Comments »

In August 2006, the International Astronomical Union (IAU) voted on a definition of “planet”. To be considered a planet,

1. The object must be large enough to be spherical under its own gravitational force.  This is a general principle:  if a chunk of rock or a ball of gas has enough mass, it tends to become spherical just because that’s the way  gravity works.  Smaller objects, like pebbles or baseballs, can be spherical for other reasons, namely erosion or forces other than gravity, so some Solar System bodies lie on the boundary of this criterion.  Two examples of this are the asteroids Vesta and Pallas, which appear to be roughly spherical, but might not quite be massive enough to count.
2. The object must orbit the Sun directly.  Certain moons, like Ganymede (which orbits Jupiter) and Titan (which orbits Saturn), are actually more massive than Mercury, and Titan has a thicker atmosphere than Earth.  However, since they orbit planets rather than following a direct orbit around the Sun, they don’t count as planets in their own right.
3. The object must dominate its orbit.  In other words, the body must be the most massive object in its neighborhood.  It also, by virtue of its gravity, cleared most of the smaller objects out of its path, so that impacts won’t substantially change its orbit.
4. The object must be small enough that it doesn’t emit its own light via nuclear fusion.  Planets don’t emit their own light:  we see Venus, Jupiter, and the like by the light they reflect from the Sun.  Stars like the Sun, on the other hand, compress the hydrogen atoms in their cores so much that they fuse into helium, releasing a huge amount of energy in the form of light.  This criterion isn’t terribly important for our Solar System, since Jupiter (by far the largest planet) comes nowhere near the threshold for becoming a star.

Continue Reading »

Posted by Matthew R. Francis under Science Ideas & Science News | No Comments »

Is there water on Mars?  We know the answer is “yes”, since Mars has ice caps at both poles that grow and shrink with the seasons.  The real, harder questions are:  how much water is on Mars, and where is it located? Continue Reading »

Posted by Matthew R. Francis under Science Ideas & Science News | No Comments »