Jupiter, and the topic of a "dwarf Planet" (Pluto).

One of the visitors had a quick question about Jupiter. Being pretty busy and perhaps a bit lazy I didn't bother to study and refresh my mind with some basic astronomy facts that I should know and should study. I need to study these basic facts better. I just referenced the young man to George as the resident expert inside the observatory. I found that the easiest way to quickly get the answer at that time.

George replied that Jupiter was 80,000 miles in diameter, which is a good round number and gives you an idea of the size of Jupiter. Of course we can look up facts on the web or in a good reference book and finding the answers in books or on the internet can be fun as well. I didn't spend the time to show a really nice program on the iPad and iPhone that will listen to a question and provide a quick search to a question. This is called Dragon Search and is a popular App on the iphone and iPad devices. It's a free application as well. If I asked that question inside the Dragon Search application, it would listen to my question go out to a website interpret my question and type what I spoke into a search engine. Rather than do a search I just had George answer the question. Later at home I fired up my computer and did a google search and quickly found a website that has a lot of interesting answers and facts about astronomy:

http://www.universetoday.com/

This is an interesting site and for those of you on the internet reading this you can do a google search on "how big is Jupiter" and find many links, one of them to the above site.

http://www.universetoday.com/guide-to-space/jupiter/how-big-is-jupiter/


So we can see Jupiter is about 88,000 miles in diameter.

There's a lot of good information about the other planets on the web as well. Let's talk a moment about our ninth planet or is it a ninth Planet? It depends on who you ask. To older folks, we often still think of this as the ninth planet, Pluto.

Pluto is now considered a dwarf planet.

Old timers like me and many other amateur astronomers want to cling to the old facts we've learned over the years and say there are nine planets and Pluto is the ninth one. Because Pluto was thought of as the ninth planet for many years and we are used to reading and hearing Pluto is the ninth planet. It's difficult to unlearn "a fact" we've all been hearing about for all these years. It would be like someone calling your big pet dog just another wild prairie dog, more like a rodent than a pet poodle.

Pluto was the ninth planet discovered. Most adults were taught that in school, so we are used to thinking of it as the ninth planet, because it was "a well known fact of Astronomy" for so many years.

I even have two solar system charting apps/programs that some of us looked at last night. I like the charting program that shows Pluto as a planet. The other charting program doesn't even show Pluto at all.

So one charting program shows it as a planet, the other doesn't.

Can we teach an old dog new tricks (or facts)? Many Amateur old timers don't want to hear that Pluto isn't a Planet and now is some kind of "dwarf" planet. I could probably start a debate at the FAAC club meeting and members could talk for perhaps hours debating why Pluto should be a planet. And most of the members at the club might say, "I think it's a planet, because I always heard it was a planet and learned to call it a planet, so for me it's a planet."

When you read the following link, you can see why Pluto is now considered by many astronomers to be a dwarf planet.

http://www.universetoday.com/2008/04/10/why-pluto-is-no-longer-a-planet/


Maybe if we had some kind of new Pluto mascot or something, like an additional dwarf in a fairy tale named Pluto, we'd have a better feeling about calling it a "dwarf planet". Maybe we need a new Disney rendition of Snow White to add an eight dwarf and call him Pluto. What do you think?

Some think Pluto was named after the disney character Pluto, which is not really true.

How would Pluto look in the C-14 telescope?

(Hint: Most bigger telescopes have a "visual magnitude rating", which shows you what you should be able to see visually. . . but we often cannot see objects at that faint limit, because the sky conditions are not good enough and also many of us may not have as good a set of eyes as the manufacturers would list for visual viewing. Magnitude is a rating of faintness of a light source and stars or objects are often listed as being a certain "magnitude". If the telescope can't see at that magnitude visually, you won't be able to see that object in the telescope, and often you may not be able to see an object even close to the rating, especially in a bright city setting.)

If it was clear out it would be very difficult for us to see and realize where Pluto was, because it's very faint. It has a very faint appearance and that is referred to as a number which we call magnitude. A fainter star or planet has a larger magnitude number. A bigger telescope can see fainter stars. A telescope with a bigger diameter mirror or lens can see a fainter star. The large lens or primary mirror will bring in more light and that means in theory we can see fainter stars, up to a certain point. In "bright skies" it can be more difficult to see very faint stars, because the brightness and haze or pollution may cause conditions to be much poorer to view a faint object. If you look around and are older, you'll notice you cannot see as much in the bright cities as you could in the old days. Because in the old days many cities were much smaller and the towns and countryside were not lit up like they are today. That sky glow makes it more difficult to see faint objects. Sky glow and pollution can even affect what a large telescope can see. We might be able to see Pluto with the C-14 at a dark sky site under ideal conditions. But it would be very difficult for most of us to see it, because it's so faint. Pluto is often very faint and could be 15.1 magnitude in faintness which is very faint indeed. The C-14 can in theory see objects as faint as 15.3 which means in theory with the best eyes in the darkest skies someone might be able to see Pluto through a C-14. But in the Lincoln Park Observatory with all the bright lights and sky glow and often poor conditions due to dust, clouds, ice crystals and other stuff in the air, you're not going to be able to see down to the 15th magnitude. For faint fuzzy objects I've found we can rarely see below the 10th magnitude and observe Messier objects, but that was one night and conditions could vary a bit depending on sky conditions. So I can safely say it's very unlikely that anyone would ever see Pluto even as a star in the C-14 in Lincoln Park, Michigan.

CORRECTION: I'm learning a bit more about this as you can see, just because I help out at the observatory doesn't mean I'm immune to making mistakes. Okay here's a revision on the discussion of the ability of the telescope at the observatory. First we may have had a difficult time seeing 10th magnitude M objects, which are galaxies or faint fuzzy objects like nebula objects. The magnitude rating for these is the total brightness over the entire area. A star is a point of light. So a star could be magnitude 12 for example and be clearly seen because it's a point of light, where a 12th magnitude fuzzy object might be very faint at any one point of it's location that we are looking at, so it would register and seem to be much fainter, because it's less concentrated. With a larger light signature. So you may not be able to see a 10th magnitude faint fuzzy object on a given night with a given scope, but a star or far away planet would have a smaller area and brighter overall appearance, so it might register. George mentioned that the C-14 should be able to see 15.5 magnitude and Pluto may be at only 14 magnitude, so in theory we can see Pluto naked eye with a C-14, but there's a catch. . . it would still have to be a dark sky location with good seeing conditions. We actually don't have a good enough site to likely see Pluto at 14th magnitude. I'm mentioning this because some might think we cannot see stars that are more faint than 10th magnitude with the C-14, but we can. (Thanks George for the clarification.) Sometimes it's good to chat these over with more experienced observers, before posting stuff on a web blog.)

We should be able to register Pluto on a photograph, but this would likely depend on the sky conditions. (End of revision.)

If we looked at Pluto and saw it with a large telescope, we'd see a small faint dot that looked like a star. We wouldn't see a disk like planets that are closer to us. We'd see a star like image. We wouldn't see it look much different from other stars of the same brightness. (Back in 1930 a 13 inch telescope was used to photograph Pluto, so with the right conditions and a perfect site, it might be possible to photograph Pluto.)

Pluto would look like a small star if we had really good conditions and a really big telescope to look at it. It would look like a small star to us and we'd likely have to use a camera to see it, even with the big telescope we have at the observatory. To realize Pluto was not a star, we'd might need to look at different photographs we'd take of it and see it move over time from one photograph to the second one taken later.

http://en.wikipedia.org/wiki/File:Pluto_discovery_plates.png


http://en.wikipedia.org/wiki/File:Pluto_discovery_plates.png

Pluto often looks like another star and we know it's not just another fixed star, because it moves when we take different photographs of it from one day to the next or one week to the next. It would of course move more between one week to the next, because it would have more time to move against stars which would be much further away and in the background. They'd appear to be fixed in space and wouldn't look like they were moving to us at all. We'd see it move from one photograph to another and the other stars would appear to be fixed in the two photographs from one week to the next for example.

Any faint objects that move could be asteroids, a comet or some other object. George even has a good story about a UFO that looked like a star and can tell you this story if you ask him some time when you visit the observatory. It wasn't a star or an asteroid he was seeing in a photograph he took. What was it? You'll have to stop by and ask him to find out.

So the planets, asteroids and comets will move against the background of stars that are much further away and if they are moving a lot, they are probably a lot closer to our vantage point or earth's orbit. Sometimes asteroids come pretty close to earth. Jupiter actually stops some asteroids and comets, it's large gravity captures the object and the object will crash into Jupiter before it could get close to our orbit. I'd rather have a large asteroid or comet crash into Jupiter than earth, wouldn't you?