The Face On Mars?!?!

We can't help but speculate the idea that life exists on other planets, and it's been long thought that alien life may exist on planets as close to us as Mars! One of the iconic images that really got people thinking is this photograph of the Martian surface taken by the Viking 1 Orbiter in 1976.

Notice anything strange about the picture? (Remember, Photoshop wasn't invented yet!) Clearly there is some sort of rocky structure that looks like a human face!  Is this evidence for an ancient Martian civilization? Maybe it's the Martian's Mount Rushmore? For almost 25 years after this image was taken it dazzled the world and created a hype about the possibility of alien life. In 2001, the Mars Global Surveyor took a closer look at the structure, hoping see more evidence of civilization. Sadly (at least for those who like alien hunting), the new sharper image of the face on Mars revealed that it is just an ironically shaped mountain that when viewed at low resolution happens to resemble a human face (see below).

 I know, I know, definitely not the ending you were hoping for. But the search for alien life on Mars is still on! Stay tuned for further updates ...

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Image Credits: NASA/JPL

Haumea, The Egg Shaped Dwarf Planet

The term dwarf planet is a new classification of astronomical bodies. A dwarf planet is a body that is within our solar system, but is too small or has to strange of an orbit to be classified as a regular planet. Pluto is now a dwarf planet, along with a handful of other objects in the Kuiper belt (the chain of "leftover" planet material  at the edge of our solar system). Most dwarf planets are small, round and rocky, and some even have moons! Haumea (pronounced how-me-ah) is a dwarf planet in the Kuiper belt with two peculiar properties:

 1) It is believed to be egg shaped
 2)  It's made of Crystalline water

 

The image above is an artists impression of what we think Haumea and its moons look like.

As you may have noticed, pretty much everything in the universe (except for galaxies) is shaped like a sphere. Why this planet is shaped like an egg, no one knows. It's also incredibly strange that it's made of crystalline water. It's too far away from the sun, and therefore not  technically warm enough, to have water in crystal form on its surface. Astronomers have a few theories about how this could happen, but it's still in the investigation stage. It's funny, most people think that astronomers know everything there is know about the universe, especially our solar system. And yet there is still so much more to learn!

Image credit: NASA

Galactic Cannibalism!

 Galactic cannibalism…. Just the name must intrigue you!

If two galaxies traveling through outer space happen to pass close enough to each other they will interact. Often they will be "nice" and just push and tug on each other a little bit, distorting their shapes.  But sometimes galaxies pass so close that they collide and consume one  another! The system above is a real Hubble Space telescope image of the whirlpool galaxy system. The galaxy on the left, and  what's left of the galaxy on the right collided a short time ago. The left galaxy was initially larger and has a larger black hole at it's center than the right one. Because of this, the left galaxy is slowly "eating" the right galaxy by stripping off all of the right galaxy's gas, dust, and stars. A true example of galactic cannibalism!

Did you know that our own galaxy, the Milky Way, expects the suffer the same fate? We are on a high speed collision course with our neighboring (and much larger) galaxy, Andromeda. When we finally collide, Andromeda is expected to cannibalize us! But don't get too worried, even though we are hurtling towards each other at 80 miles/second (yes, I mean per second!), we have about 3 billion years before the collision actually occurs. Phew!

Image Credit: NASA/HST

The Surface of Mercury

It's taken more than 6 years, but MESSENGER has finally made it into Mercury's orbit!

 

The MErcury Surface, Space ENvironment, GEochemistry and Ranging (MESSENGER) Space Probe was launched in 2004, with the purpose of studying the composition and magnetic field of the closest planet to our sun. Sending a probe to Mercury is not as easy as you might think. We can't just aim a rocket towards mercury and let the probe go; it would pass right on by Mercury and get swallowed by the sun. Instead, we must aim it such that the probe will make multiple orbits around the sun, each one honing closer into mercury's orbit. MESSENGER had to make 7 (I believe) orbits around the sun before it made it was captured by Mercury's gravitational field. The very first image send back from MESSENGER in Mercury's orbit is shown above. Mercury looks much like the moon; a small rocky body that's been bombarded by craters for years! MESSENGER plans to sends tons of pictures of Mercury back to Earth, so stay tuned for even more awesome shots of this little planet!

Image Credit:NASA/JHU APL/CIW

Why is the Sky Blue?

Have you ever wondered why the sky is blue? Or why sunsets exhibit such pretty colors? Well the answer is pretty simple, and of course involves astronomy!

  

The Sun emits what we perceive as white light. If you send a beam of white light through a prism, you will see that it breaks up into all the colors of the rainbow. Each color of light has a different wavelength and therefore a different energy.

Gas molecules in the atmosphere have the ability to absorb and/or scatter light. And based on the type of gas molecule, it likes to interact with only certain colors of light. The atmosphere is made mostly of nitrogen and oxygen. These two molecules tend to let all colors of light pass by unharmed, except for blue light. Blue light has just the right energy to be absorbed and scattered by the gas. Therefore we have lots of blue light bouncing around in the atmosphere, making the sky appear blue!

 When you look along the horizon you're actually looking through more atmosphere than when you look straight up. When the sun rises or sets, the light initially has to pass through more atmosphere than usual. Because of this, red light has a harder time getting through the atmosphere and is often scattered along with the blue light, making the sky appear reddish purple. You can thank astronomy for those pretty views!

Kepler's Planet Discoveries

The image below is today's Astronomy Picture of the Day. It's not a compilation of photographs,but a representation of stars that have planets orbiting them.

The Kepler mission was launched in 2009,with the goal of discovering Earth like extrasolar planets (i.e. planets that revolve around other stars besides our sun). To do this, Kepler looked at hundreds of thousands of stars and watched to see if they got any brighter or dimmer. If the brightness of a star dropped, it might be due to a planet crossing in front of it. We experience this all the time in our own solar system. When Venus appears to cross in front of the sun from Earth's perspective, the Sun looks dimmer by about 0.2%. It's not something we notice with our eyes, but telescopes can easily measure this subtle change in brightness. Using this method, Kepler found 1,235 potential exoplanets! The image above represents each host star (yellow/orange) and the planet crossing in front of it (black circles). Based on the data Kepler receives, we can figure out where the planet crosses the star (top, middle, bottom, etc.) and about how big it is. Telescopes today do not have the power to directly image most exoplanets, but Kepler's method proves incredibly successful. If you look closely at the image, you might even see some multi-planet systems!

Illustration Credit: Jason Rowe, Kepler Mission

Go to APOD.NASA.gov to see a higher resolution image

What's Your Sign? The True Zodiac

As much as I hate it when people assume that astronomy=astrology, I love sharing this little bit of information….

 

Your astrological or zodiac  sign (whether you’re a Libra, Taurus, etc.) has to do with the constellation that was highest in the night sky the day you were born. These constellations fall on the ecliptic, which is the path that the planets take across the night sky. There are 12 constellations and therefore 12 zodiac signs that appear for about a month at a time throughout the year. All this was put together by the ancient Greeks back a couple thousand years ago, and has been in pop culture ever since. There isn't a single newspaper nowadays that doesn't give you your daily horoscope. Well I'm sorry to disappoint all of you that live by your horoscope, but the zodiac sign you thought you were is wrong. (What! But my personality fit so nicely with my zodiac sign! How could this be true!) Pop culture never took into account that the stars and our solar system move. In the past couple thousand years, our solar system has revolved around our galaxy, and changed position enough such that the stars in the night sky don't appear at the same time that they used to thousands of years ago. So now instead of the Libra constellation being highest in the sky in early October, it's highest in early November. You can figure out your true zodiac sign using your birthday and the list below. Note that some people want to define a new zodiac called Ophiuchus, but it hasn't really been accepted into pop culture yet.

Capricorn - Jan 20 to Feb 16

Aquarius - Feb 16 to Mar 11

Pisces - Mar 11 to Apr 18

Aries - Apr 18 to May 13

Taurus - May 13 to Jun 21

Gemini - Jun 21 to Jul 20

Cancer - Jul 20 to Aug 10

Leo - Aug 10 to Sep 16

Virgo - Sep 16 to Oct 30

Libra - Oct 30 to Nov 23

Scorpius - Nov 23 to Nov 29

Ophiuchus - Nov 29 to Dec 17

Sagittarius - Dec 17 to Jan 20 

I told this to someone the other day and they were devastated. They lived their life by their horoscope and couldn't believe that it had changed. Hope this doesn't burst your bubble!

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