What is Project 1640?

Detecting Extrasolar planets is tough work. Most of the detections gave been indirect (only 5% of exoplanets have been observed directly). Now, a new promising method of exoplanet detection is debuting and it is called Project 1640. However, before we describe what Project 1640 is all about, let's review all the current methods that we can use to detect an extrasolar planet outside of our Solar System:

1) Radial Velocity Method: AKA Doppler Spectroscopy. This method basically watches for a star to wobble. What does a star wobble mean? It means that the star is being gravitationally affected by its own orbiting planets. Both planet and star both tug on each other through gravity. Have you ever spun in a circle with a friend, hands locked together? Did you notice that you kind of have to lean back in order for both of you to spin smoothly. What this does is it creates a kind of "center" between the both of you. Suns and their planets do the same thing. As they spin together, the sun will oscillate back and forth - wobble in place - in accordance with the strength and speed of the planet that is orbiting. This method excels at detecting planets larger then Jupiter, generally. This is because larger planets cause their parent stars to wobble considerably more than smaller planets, thus making the star's wobble easier to detect. This wobble effect is detectable because of the Doppler Effect. The frequency of light waves change as the object emitting them is in motion. And this change in frequency is detectable.

2) Astronomical Transit: This method of exoplanet detection consists of watching and measuring the total amount of light emitted from a particular star. Noticable and perhaps regular changes in that amount of light can be an indication that a planet is passing in front of its parent star, relative to our position in space. Theoretically, an orbiting planet would block a detectable and regular amount of light on a regular basis. The longer a star is observed, the greater the chance that a planet will show itself. Why is this? Well, consider the case of Mercury versus Neptune. Mercury orbits the sun every 88 days. So, if you looked at the sun and measured its light, waiting on a detectable drop in the amount of light, you would only have to wait a maximum of 88 days. If you wanted to see Neptune, you would have to wait a maximum of 165 years! So, longer observations of stars are better. However, the planet must pass in front of its parent star relative to our position in space. Most solar systems out there are probably not so fortunately positioned.

Pulsar in the Crab Nebula

3) Pulsar Timing: Pulsars are neutron stars that double as gigantic magnets - the most powerful in the universe. One of the qualities of a pulsar is a beam of high energy that is spewing out of it. Pulsars have very regular rotations. In fact, Pulsars are generally regarded as the clocks of the galaxy. This means that they are very regular. So regular you could probably set a clock by them (listen to some Pulsars here). Any changes to that regularity, however, can be used to determine a pulsar's motion in space. With the proper number crunching, you can tease out the parameters of an orbit. Not only that, but this method is extremely sensitive. It is said that exoplanets a tenth of the size of Earth can be detected in this way. Unfortunately, pulsars emit high doses of radiation - extremely HIGH AMOUNTS. This property effectively makes planets that orbit pulsars inhospitable for LAWKI (Life As We Know It). The first planets found outside of our Solar System were found this way.

4) Phase Reflected Light: Large, Jupiter-sized planets orbiting close to their parent star can go through phases, just like our Moon (relative to our position in space, of course). While we can't see the planet directly in this manner, what we can see is a difference in the total amount of light being emitted. Starlight, bouncing off an exoplanet surface, can add to the overall amount of light the same way that shining a flashlight in a dark room full of mirrors can be brighter than a room without mirrors. You can think of this method as the opposite of Astronomical Transit, mentioned above. Astronomical Transit waits to see a dimming of starlight to infer a planet's existence. Phase Reflected Light waits to see a brightening of starlight to infer a planet's existence.

5) Gravitational Microlensing: This method will sound the craziest, so hold on to your thinking caps. What must happen in order to infer a planet's existence in this way you must have two stars in two completely separate star systems. And they have to line up relative to our own solar system. Tall requirement, huh? When it happens, the light from the background star will be distorted by the gravitational field of the forground star as that light passes through the foreground system on its way to Earth. I know what you are thinking...Geordi LaForge said the same thing once, didn't he? If the foreground star has a planet in orbit, then that planet will contribute further to this microlensing effect. This affected light can be studied and the orbiting planet of the foreground star can be inferred.

6) Direct Imaging: The last of the tried-and-true planet detecting methods is that of directly imaging a planet. This is very, VERY tough. This is because light from a star typically overpowers any reflected light that comes from the planet. So, what if we blocked out the starlight completely and exactly and then looked for the light reflected from the planets? Bingo. And that is the gist of direct imaging, except that its still very hard. Researchers use mirrors or they can diffuse the light. Either way, it takes expensive equipment and complicated math.

Finally, what is Project 1640? As the American Museum of Natural History puts it: "The combinations of an advanced adaptive optics system (PALM-3000 or P3K) on the 5-meter diameter telescope at Palomar Observatory, an advanced coronagraph and hyperspectral imager called project 1640 developed at the American Museum of Natural History, and a wavefront sensor calibration unit provided by the Jet Propulsion Laboratory offers a broad range of research opportunities. Project 1640 is specifically designed to image planets orbiting nearby stars and to acquire low-resolution spectra of them simultaneously. It is currently the most advanced and highest contrast imaging system in the world and was successfully installed at the Palomar 200-inch telescope in 2008"

Write up by Popular Science: "Its adaptive optics system can make more than 7 million active mirror deformations per second, with a precision level better than one nanometer. Its wavefront sensor, which  detects the atmosphere-caused deformations of light hitting the telescope, is also sensitive to a nanometer. As the sensor detects perturbations of light waves coming into the telescope, it continually adjusts and conforms to block out the light as effectively as possible. The system can resolve objects 1 million to 10 million times fainter than an object at the center of an image, which is usually the star. With that level of sensitivity, astronomers may be able to see planets."

Project 1640 promises to be a brand new thing in exoplanet discovery. As of July 2012, it is up and running. We absolutely look forward to seeing the results of this new initiative. For now, you can get more in depth information from the following websites:
Caltech
The American Museum of Natural History
Popular Science
NASA Jet Propulsion Laboratory
Engadget

Stay tuned for more information on Project 1640.