Other Solar systems

Hello Everyone!

In my last post, I talked about what stars were. In this post I will talk about other solar systems and what is involved with what's out there.

The first thing that we will talk about is how other solar systems are located. The most common method is Doppler spectroscopy, a technique that has located around 90 % of exoplanets. It uses radial velocity measurements through examining Doppler shifts in the spectrum of a star around which the planet orbits. Astronomers look for tiny changes in a star’s radial velocity. For example, Jupiter causes the sun to change velocity by about 13 metres per second over a period of 12 years. By tracking these changes over time, astronomers can estimate a planet’s minimum mass.

Another way to identify an exoplanet is to watch the brightness of a parent star. If it dims for a short time, it could indicate a transit – a planet crossing in front of the star. This has been the second most useful method of discovery, but it does lead to a number of false positives. In addition, some astronomers use astrometry – pinpointing the position of a star in the sky and seeing how it makes tiny changes in its positing, which could indicate a planet nearby. This is called star wobbling.

The next point that we will talk about is what an AU actually is. In astronomy, you may have heard it here or there, something is so many AU away, etc. AU is actually short for Astronomical Unit. It is 149,597,871km or the distance from the Earth to the Sun.

Convert the following AU to km.

1. 23
2. 86
3. 47
4. 92
5. 12

Figure 1: An example of other solar systems and comparing them to our own.

The third and final point that we will be talking about today is deep space probes. Do you remember names like Pioneer, Explorer, Mariner, Venera, Luna, Ranger, Voyager, Zond, or Surveyor? Many of the early probes launched by the United States and the former Soviet Union have borne these names. Soon after the Soviet Union launched the first artificial satellite, Sputnik 1 on 4 October 1957, both the former Soviet Union and the United States began to launch a flurry of probes to the Moon, Mars and Venus.

So, just what is a space probe, anyway? A space probe is an un-piloted spacecraft that is used to make observations and send information back to Earth regarding these observed objects. While many satellites are also space probes, we will be discovering those which have escaped earths gravity. These probes carry sophisticated equipment, such as infrared sensors, radars, ultraviolet sensors, magnetometers, soil analysers, spectrometers, and sensors to study wind velocities or chemical compositions. They are various cameras, navigation, and communications systems. There also has to be a power supply and protection against heat, cold, and cosmic radiation. Exactly what equipment is on any deep space probe, of course, depends upon its mission.

Answers to previous questions:

1. Yes, close one eye and pick an object, now switch eyes. Has it moved? That is parallax.
2. Alpha Centauri, Algol, Beta Lyrae

Research Questions:

1. What is the most successful deep space probe so far?
2. What is the largest planet found outside the solar system?
3. What does the space telescope COROT do?
4. What is the smallest planet found outside the solar system?

Q:What did the alien say to the garden?

A: Take me to your weeder!

Enjoy! :)

Emily.