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Tom Mazanec
2010-Mar-01, 06:33 PM
What will produce the first map of an extrasolar planet?

Rhaedas
2010-Mar-01, 06:42 PM
Depends on what you mean by a map. We have crude images of Pluto already with Hubble that we can use to determine a lot, but they aren't really maps. If you're wanting to see details, then a flyby is about the only way, even with lensing technology.

Ara Pacis
2010-Mar-01, 07:49 PM
What will produce the first map of an extrasolar planet?

Some guy with a pen or pencil is my guess. "Here be dragons" may as well be on it for all we'd likely know.

Bluevision
2010-Mar-02, 03:23 AM
^^ Fully agree. We've already "mapped" a bunch of them :)

I'm guessing it's going to be some sort of flyby. I mean, planets are really small things, right? Even if you had an absolutely huge telescope, it'd be really, really hard to see, right?

Hungry4info
2010-Mar-02, 12:06 PM
Other.
Spacecraft: Spitzer
Target: HD 189733 b.
Wavelength: IR

http://en.wikipedia.org/wiki/HD_189733_b#Map_of_the_planet

NASA released a brightness map of the surface temperature of HD 189733 b; it is the first map ever published of an extra-solar planet.

Tom Mazanec
2010-Mar-02, 02:07 PM
Wow. I didn't know we already had one. Things are moving even faster than I dreamed.

Hungry4info
2010-Mar-02, 02:53 PM
Exciting isn't it! :)

eburacum45
2010-Mar-02, 02:59 PM
I would point out that map has a very low resolution, so low that if the Earth were a feature on the surface of that world, it wouldn't show up.

But it is a good start.

IsaacKuo
2010-Mar-02, 03:10 PM
I don't think that counts. It is a "weather map", which I don't think fits the spirit of the original question. A "map" should be a picture of relatively permanent features--something which someone could navigate by, in principle.

But a "weather map" is a picture of something which is constantly changing on relatively small time scales, so you couldn't navigate by it (other than to know to avoid storms, obviously).

Hungry4info
2010-Mar-02, 03:23 PM
But a "weather map" is a picture of something which is constantly changing on relatively small time scales, so you couldn't navigate by it

Well, HD 189733 b is a gas giant planet. Under that rationale, the "maps" of the gas planets in the solar system would not count as "maps" either.

Even still, the infrared features noted are permanent. The heating flux from the star is continuous and winds always push the hottest part of the planet eastward.

The author of the OP seemed satisfied with the IR map. If IR wavelengths do not count, which set of wavelengths do? And how will this affect what we call the "maps" of Venus and Titan?

IsaacKuo
2010-Mar-02, 04:13 PM
Well, HD 189733 b is a gas giant planet. Under that rationale, the "maps" of the gas planets in the solar system would not count as "maps" either.
Within the spirit of "a map is something to navigate by", then that's correct. Gas giants are swirling masses of fluid with multiple bands rotating relative to each other. It's possible that there simply isn't anything "solid" to navigate by--not even deep down.

Even still, the infrared features noted are permanent. The heating flux from the star is continuous and winds always push the hottest part of the planet eastward.
It's permanent in the same sense that Earth's day and night sides are permanent.

The author of the OP seemed satisfied with the IR map. If IR wavelengths do not count, which set of wavelengths do? And how will this affect what we call the "maps" of Venus and Titan?
It's not a question of the wavelength, it's a question of what you're looking at. The radar maps of Venus and Titan are spiritually "maps" in the traditional sense because they show features that you could navigate by, if you were travelling around on them.

A "map" isn't a map because of how the data was gathered, it's a map because of what you can do with it.

Paul Beardsley
2010-Mar-02, 04:34 PM
I don't think that counts. It is a "weather map", which I don't think fits the spirit of the original question. A "map" should be a picture of relatively permanent features--something which someone could navigate by, in principle.

But a "weather map" is a picture of something which is constantly changing on relatively small time scales, so you couldn't navigate by it (other than to know to avoid storms, obviously).

You're probably right, but still. Even an incredibly low-resolution sort-of weather map is far more than I ever expected to see in my lifetime.

It's not just pretty lights, they're real places out there.

Hungry4info
2010-Mar-02, 05:05 PM
Some interesting points, IsaacKuo.

What would you consider then to be a map of a gas planet? Or would they be un-mappable.

eburacum45
2010-Mar-02, 06:06 PM
Jupiter has several well-defined zones and bands, as well as a red spot which appears to be of long duration. A map of Jupiter would be very useful if you wanted to find regions of upwelling and down draft.

Saturn seems to have a semipermanent hexagonal feature at its north pole, and a cyclone at its south pole- but these might change or even switch places as the planet moves though its seasons. Maps of gas giants are useful- but they must be expected to change. Don't forget that the Earth's geography changes too, just on a much longer timescale.

Ara Pacis
2010-Mar-02, 06:51 PM
Within the spirit of "a map is something to navigate by", then that's correct. Gas giants are swirling masses of fluid with multiple bands rotating relative to each other. It's possible that there simply isn't anything "solid" to navigate by--not even deep down.Within the spirit of pedantry in yet another discipline, english, you can't navigate unless there's liquid water.


It's permanent in the same sense that Earth's day and night sides are permanent.They assume the planet is tidally locked with the star, hence the features are assumed to be permanent.


It's not a question of the wavelength, it's a question of what you're looking at. The radar maps of Venus and Titan are spiritually "maps" in the traditional sense because they show features that you could navigate by, if you were travelling around on them.The consensus is that a map, a depiction of reality, is useful for whatever you want to use it for.


A "map" isn't a map because of how the data was gathered, it's a map because of what you can do with it.Have a reference?

Hungry4info
2010-Mar-03, 01:41 AM
If, for some unfortunate reason, I was in an air balloon in HD 189733 b's atmosphere, and I had that infrared map, I would know where in the atmosphere to try to avoid.

Bearded One
2010-Mar-03, 04:01 AM
How would you select a line of 0 longitude on a gas giant?

Hungry4info
2010-Mar-03, 07:56 AM
For a tidally locked world, it is the longitude of the sub-solar point, the location on the surface where the sun is directly overhead (this applies with the moons of the solar system too, though with the planet instead of the star as the primary). For a non-tidally-locked world, the entire body rotates as a whole, but the upper atmosphere is subject to turbulence and what-not. A gas giant planet that is not in a synchronous rotation would lack a reference point, however, for 0 of longitude.

You could always choose one arbitrarily, and estimate one's longitude based on the rotation period of the planet.

IsaacKuo
2010-Mar-03, 11:47 AM
Jupiter has several well-defined zones and bands, as well as a red spot which appears to be of long duration. A map of Jupiter would be very useful if you wanted to find regions of upwelling and down draft.
This is true. If you were in an aerial vehicle on a gas giant, you'd want to know the directions of the winds and there are very well defined bands which rotate in opposite directions.

Therefore, a gas giant map would be split up into horizontal bands, with indications of the wind directions and speeds. Actually, the map would likely be in the form of a cross section. Instead of mapping longitude against latitude, you'd have a map of altitude against latitude. The wind directions and speeds likely vary with altitude.

Unfortunately, the one dimensional data on HD 189733 b is in the longitudinal direction rather than the latitudinal direction. It suggests an estimate for the global average wind direction and speed, but it can't tell us the size and directions of the individual bands.

Romanus
2010-Mar-06, 05:01 PM
Rhaedas is right; it depends on what you mean by "map". My definitions is pretty broad: a vague idea of surface variations, e.g., the crude maps of the Galilean satellites that were made as far back as the '60s with visual telescopic observations. I think that can be done with telescopes only slightly more advanced than the ones we're flying now, given sufficient occulting technology and sensitive enough detectors; perhaps Darwin or its immediate successor will be able to map albedo variations on nearby planets through their rotations to give us some unique insights.