Social Question

Symbeline's avatar

How many planets can the naked eye see?

Asked by Symbeline (30767 points ) May 6th, 2012

Or perhaps I should ask, which planets can be seen and which ones can’t? Obviously, maybe we can’t see some of the further ones. I’m aware that it’s possible to see some planets if conditions are right. Like Mars might appear as a reddish star, sometime in Spring. I really have no idea though. Maybe it’s different depending on where on Earth you are.
So out of our planets, how many can we see with the naked eye, and which ones? They probably all look like stars from far away, so the untrained eye might not know how to detect them.
I remember looking in a telescope some years back, and the owner said you could see Jupiter in it. He pointed out where, but there was just stars. Does the general populace even have strong telescopes like that at their disposal?
Inspired by Supermoon. I know absolutely nothing about space, stars and planets. so be gentle How can we even see planets anyways? They don’t have their own light source like a sun does. Or does a planet have to be in some specific position or whatever for it to be illuminated, thus allowing us to see them? So yeah, which ones can we see, how and why, and which ones can’t we see with the naked eye?

Observing members: 0 Composing members: 0

29 Answers

DrBill's avatar

ONE, Earth

if you want to talk about reflected light given off by a planet then 5, Venus, Earth Saturn Jupiter, and Mars.

If we include evidenced, then add Mercury. We can see it’s track across the sun

Symbeline's avatar

What does reflected light given off by a planet look like? Stars?

gasman's avatar

The same ones that were observed in antiquity, before the invention of the telescope. Namely, Mercury, Venus, Mars, Jupiter, and Saturn (not counting Earth, of course). That makes 5 besides Earth. Reflected light from the Sun allows them to be seen as points of light, similar to bright stars. It wasn’t until Galileo that we were aware of subtleties such as phases of Venus, rings of Saturn, etc.

Accoridng to Wikipedia, however: “Though it is visible to the naked eye like the five classical planets, [Uranus] was never recognized as a planet by ancient observers because of its dimness and slow orbit.”

Planets were distinguished from stars because they “wandered” with respect to the otherwise fixed background of the stars.

Symbeline's avatar

@gasman How did people back then figure that those were planets?

bkcunningham's avatar

There are six planets that can be seen with the naked eye. They are Mercury, Venus, Mars, Jupiter, Saturn and Uranus.

gailcalled's avatar

@DrBill : When the conditions and position are optimum, you can see Mercury with the naked
eye.

(its)

AstroChuck's avatar

Six with the naked eye. But eight can be made out if you put panties and a bra on it.

Symbeline's avatar

@bkcunningham As far as Uranus? If Pluto is no longer considered a planet, that’s the second last planet…that’s damn far. So that means we can see almost all of them.

Does anyone know if there are actual photographs of these planets on the net? All I can find is graphic reconstructions. :/

bkcunningham's avatar

They noticed the pattern of their movements, @Symbeline.

Uranus is difficult to see and you have to know when and where to look. Pluto isn’t a planet??!!!???

http://pds.jpl.nasa.gov/planets/

SavoirFaire's avatar

@DrBill Everything we see is due to light being reflected or transmitted by the seen objects, including those things we see on Earth. If you would like to give an answer to this question that is actually helpful, perhaps leave out the pseudoscientific pretension.

Symbeline's avatar

@bkcunningham Yeah, apparently Pluto is just a bunch of ice stuck together stuck in orbit, and it’s been falling apart recently, loosing chunks that float away, so they no longer consider it a planet. Don’t quote me though. And thx for the pics. :)

filmfann's avatar

Do you know what the Big Dipper is? Look for the two stars on the ladle end, and follow that line down, across the sky, and you will see a reddish object tonight. That is Mars.
Now, make a right turn, and go across the sky, and you will see a very bright star. If you looked thru a fairly powerful telescope, you will see it is in cresent (like a quarter moon). That is Saturn.
Here is a starchart for this month.

bkcunningham's avatar

April 22 would have been the best opportunity to see Uranus with the naked eye.

bkcunningham's avatar

Mark your calendars for May 20. The “ring of fire” annular solar eclipse is the first annular eclipse visible from the contiguous United States in almost 18 years. Woo Hooo!!

http://www.youtube.com/watch?v=7YX2blo1eRk

wilma's avatar

@Symbeline if I may bring up a jelly who is not (yet) on this thread.
Rarebear has some taken some great pictures including his avatar.

WillWorkForChocolate's avatar

@bkcunningham I saw uranus with a naked eye last night I’m trying to avoid making a dumb Uranus joke You can see 6 of the planets at various times.

gasman's avatar

Does anyone know if there are actual photographs of these planets on the net? All I can find is graphic reconstructions. :/

Sure, there are photographs of all the planets taken through Earth-based telescopes prior to the space age, such as this one of Jupiter. Compare to a modern image taken with Hubble here, or better yet, taken with a space probe fly-by (Cassini) here.

bkcunningham's avatar

Did you know that Uranus is also known as George? Now there is fodder for a joke.

AstroChuck's avatar

@bkcunningham- I’ll thank you to leave my anus out of it.

And I happen to be call it Gorgeous George.

Symbeline's avatar

but whenever I talk about anuses, I’m being a bad girl

LuckyGuy's avatar

Here’s a quick star gazing lesson for you. Imagine the path the sun takes when it moves across the sky, starting in the East and moving to the West. The highest point occurs around noon directly South. Got it? Now wave your hand along that line. It is called the ecliptic. All the planets and the moon move along that line plus or minus a little bit. That makes them easier to find. You don’t have to search all over the sky.
There are many websites that show the night sky. heavens-above.com is a good one. (click on the link that says “Whole sky chart” They often give the direction to celestial objects using Alt-Azimuth information. That means altitude and direction. If something is Alt – Azimuth 50 degrees, 180 degrees, that means it is at an altitude of 50 degrees above the horizon and at a direction of 180 degrees – directly South. (0 is North, 90 is East, 180 is South and 270 is West.) Direction is easy. But how do you find altitude without a transit? Even easier! Your fist is 10 degrees. Extend your arm and make a fist like you are grabbing a pole. Line up the top of your fist on the horizon. That is 0 degrees. Now make a fist with your other hand and place it on top. That is 10 degrees. Hold the top fist steady and place the other fist on top. That is 20 degrees. Keep going until you reach 50. You will be very close. The point directly overhead is 90 degrees, the Zenith. Give it a try. Try counting out 90 degrees with your fist. Go ahead. Do it! I’ll wait…. See? Magic. You are pointing overhead.
With a set of $40 binoculars, you will see Jupiter and 4 of its moons. They move around Jupiter quickly so the image is different every night. Cool.
Enjoy.
Make sure to wash the binoculars after looking at Uranus.. Sorry, I couldn’t help it.

Symbeline's avatar

@gasman Thanks for the pictures. Planets are kinda creepy looking…yet ominous, too. What are all those colors on Jupiter? I know its made out of gas. Several kinds, maybe?

@LuckyGuy Thanks for the info. I might give this a try, although I don’t have any binoculars. Might be interesting to actually see some planets and their moons. Man that makes me think, a lot of planets have several moons. Say you could actually go on Jupiter, and looked up at night, you’d see all these moons, or the ones visible at whatever spot you’re at. Then again does Jupiter or other oxygenless planets have daytime? Also I heard that some of those moons are bigger than Earth. sorry, buncha random questions

gailcalled's avatar

Length of day and night on the planets

This is predicated on the length of the rotation of the particular planet. Earth rotates approximately every 24 hours, for example.

Symbeline's avatar

Holy crap. A day on Venus sure is long. :O

LuckyGuy's avatar

@Symbeline I think the night sky would be fantastic. So far they have discovered more than 60 moons! Also the big 4 (discovered in the early 1600s) whip around Jupiter much faster than the 28 days it takes our Moon to go around Earth. You can look up the exact numbers but if I recall correctly the 4 biggest moons of Jupiter orbit about every 2 days, 4 days, 8 days and 16 days. Wouldn’t that be awesome to see? And once every X number of years they would be lined up in the sky. With binoculars and a dark sky you can watch those moons move!

And these are just the planets around our own Sun. So far they have found more than 150 other planets (exoplanets) around other stars. Every year they find more. I’m willing to bet in 10 years we will know of at least 2000!
(And there are people who think we are alone in the universe. Oh Puhleeeze!)

Symbeline's avatar

Man that’s messed up, seeing a bunch of moons move around. That would be something indeed. Are all those moons (I think Saturn has several too) like, the same as ours? besides size?
And yeah, about other planets. I’ve been wondering about that too, planets from other solar systems. I knew some were discovered, or at least, it’s confirmed that there are other planets out there. But 150? There’s gotta be some kind of life somewhere on some of those. Do people have any details about them? Like how big they are, what they’re made out of and all? I heard they found this one planet that has a condition very similar to Earth and that life as we have here could easily thrive there, but since it’s trajectory takes it so far away from its Sun at a certain point, everything freezes so whatever life could thrive doesn’t get to. But when it gets closer to its Sun, there’s water and earth and stuff. I think they called it Titan, but I can’t remember. :/

wilma's avatar

@Symbeline The planets don’t “twinkle” like the stars do. It’s pretty easy to find Venus, it’s the brightest thing in the night sky after the moon. Mars is pinkish and Jupiter looks very round, like a small polka-dot in the sky.

LuckyGuy's avatar

@Symbeline I looked up Exoplanets and see that my information is at least a year old. As of this week they have found 763 planets! They figure there are 100 billion stars in our galaxy and on average there are 1.6 planets around each one. Right now our detectors are limited. to seeing large planets that are relatively close to their nearby star. You know that will improve.

gasman's avatar

@Symbeline About the colors of Jupiter: According to the Wikipedia article on Jupiter:

The clouds are located in the tropopause and are arranged into bands of different latitudes, known as tropical regions. These are sub-divided into lighter-hued zones and darker belts. The interactions of these conflicting circulation patterns cause storms and turbulence. Wind speeds of 100 m/s (360 km/h) are common in zonal jets. The zones have been observed to vary in width, color and intensity from year to year, but they have remained sufficiently stable for astronomers to give them identifying designations.

There’s also the “Great Red Spot,” which is basically a permanent storm similar to hurricanes on Earth. The single spot, however, is bigger than the entire Earth. Here’s a time-lapse video of it. Funny that you think it’s creepy or ominous, because I think it’s a thing of beauty. Imagine watching it change day after day from the vantage point of one of Jupiter’s moons.

Answer this question

Login

or

Join

to answer.
Your answer will be saved while you login or join.

Have a question? Ask Fluther!

What do you know more about?
or
Knowledge Networking @ Fluther