# Why Do Some Satellites show a "Hole" at the Poles? Hollow Earth? [Inclined Orbit]

#### Supreme Logic

##### New Member
Can anyone explain the reason as to why NASA would launch 2 polar orbiting satellites, but NOT scan the very center? where HE theorists believe the entrance is....

Here are some links to NASA that show what they call the "Polar Hole". They use this term in more than one PDF file, but I cant find the other one anymore....

They go further by describing how they simulate a scan of the center by using "interpolation" and "Gaussian kernal".

http://icesat.gsfc.nasa.gov/icesat2/publications/pubs_2010/abdalati_et_al_2010.pdf
(scroll to page 8)

http://celebrating200years.noaa.gov/visions/satellites/welcome.html#collab
(another example of the "polar hole")

http://www.nasa.gov/centers/goddard/news/topstory/2003/1209icesat.html
(general info)

https://science.nasa.gov/missions/icesat
http://visibleearth.nasa.gov/view.php?id=86036
(more polar holes)

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Polar orbiting satellites are generally in inclined orbits to keep the orbit "frozen", if they did not do this then the orbit would drift. The most obvious reason to do this is to save fuel.
https://en.wikipedia.org/wiki/Frozen_orbit
In orbital mechanics, a frozen orbit is an orbit for an artificial satellite in which natural drifting due to the central body's shape has been minimized by careful selection of the orbital parameters. Typically this is an orbit where, over a long period of time, the altitude remains constant at the same point in each orbit[1]—changes in the inclination, position of the lowest point of the orbit, and eccentricity have been minimized by choosing initial values so that their perturbations cancel out.[2] This results in a long-term stable orbit that minimizes the use of stationkeeping propellant.
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With some satellites, the inclination is picked to maintain a sun-synchronous orbit, so they pass over all areas of the earth at about the same time of day (and night, for the other side)
https://en.wikipedia.org/wiki/Polar_orbit

Near-polar orbiting satellites commonly choose a Sun-synchronous orbit, meaning that each successive orbital pass occurs at the same local time of day. This can be particularly important for applications such as remote sensing atmospheric temperature, where the most important thing to see may well be changes over time which are not aliased onto changes in local time. To keep the same local time on a given pass, the time period of the orbit must be kept as short as possible, this is achieved by keeping the orbit lower to the Earth. However, very low orbits of a few hundred kilometers rapidly decay due to drag from the atmosphere. Commonly used altitudes are between 700 km and 800 km, producing an orbital period of about 100 minutes.[2] The half-orbit on the Sun side then takes only 50 minutes, during which local time of day does not vary greatly.

To retain the Sun-synchronous orbit as the Earth revolves around the Sun during the year, the orbit of the satellite must precess at the same rate, which is not possible if the satellite were to pass directly over the pole. Because of the Earth's equatorial bulge, an orbit inclined at a slight angle is subject to a torque which causes precession; an angle of about 8 degrees from the pole produces the desired precession in a 100-minute orbit.[2]
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ICESat is at 94 degrees which is not sun-synchronous, but is instead a "frozen orbit" closer to the pole. The actual orbit is picked based on exactly what they want to study, and constraints of the mission technology.

http://www.csr.utexas.edu/glas/Mission_Description/

The orbit planned for use is known as a "frozen orbit", meaning that in spite of the Earth's oblateness, the perigee will remain fixed (in an average sense) at the northernmost latitude (essentially at the North pole). Accounting for the fact that the Earth is an oblate spheroid, the following range of altitudes (with respect to mean sea level) will exist for both orbits:

Near the North pole - 605 km
Near the South pole - 623 km
Near the equator - 593 km​

Since the orbit is frozen, perigee does not circulate and the altitude will be a function of latitude. The orbit inclination was chosen to be 94 degrees. This inclination provides coverage to 86 deg latitude, thereby ensuring coverage of the fast-flowing Antarctic ice streams that flow onto the Ross Ice Shelf. The retrograde inclination was chosen for the geometry of crossovers, the intersections between the ascending and descending ground tracks. Crossover points are a key analysis technique to meet the science requirements.
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The Terra and Aqua satellites are inclined away by 8 degrees, but take images of a wide enough area that they cover the poles (assuming it's summer there). Here's yesterday's image of the South Pole
https://worldview.earthdata.nasa.go...as=2016-10-18&ae=2016-10-27&av=3&al=undefined

The North Pole looks like:
https://worldview.earthdata.nasa.go...as=2016-10-18&ae=2016-10-27&av=3&al=undefined

Not because Terra is avoiding the North Pole, but because it's winter there. Go back one month and there's less

And two Months are we are back in summer:

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Thank you for the wealth of info Mick, ill check it out thoroughly.

The thing that sticks out still is that they seem to admit that they dont scan the middle, and for that reason they use "interpolation" and "Gaussian kernal" to fill in the hole. (seen on page 5 of the PDF)
http://icesat.gsfc.nasa.gov/icesat2/publications/pubs_2010/abdalati_et_al_2010.pdf

Maybe im misinterpreting how "interpolation" and "Gaussian kernal" work??

Either that or its an effect of photo stitching. But there seems to be some inconsistencies.
Correct me if im wrong

Not because Terra is avoiding the North Pole, but because it's winter there.
So you're saying the holes only open up in winter?

Seriously, though, that dark area is too sharply defined (and the wrong shape) to be accounted for by the darkness of the pole, so what's up? Are the orbits of the satellites shifted towards the summer side of the Earth throughout the year? Or do they just discard the data in the dark areas?

The thing that sticks out still is that they seem to admit that they dont scan the middle, and for that reason they use "interpolation" and "Gaussian kernal" to fill in the hole.
Correct. As Mick explained (and the caption on the first image you posted states) the pole itself is not covered because the inclination of the satellite is 94 degrees. So anywhere within 4 degrees of the pole (i.e 86 degrees south) cannot be imaged.

The ICESat satellite has an extremely narrow "field of view", only a few tens of metres on the ground, because it uses a laser beam to map the surface. It's not like a satellite with a camera that can take a wide-angle view. Those can cover the whole polar area, as in the Terra and Aqua MODIS satellite images Mick posted above.

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So you're saying the holes only open up in winter?

Seriously, though, that dark area is too sharply defined (and the wrong shape) to be accounted for by the darkness of the pole, so what's up? Are the orbits of the satellites shifted towards the summer side of the Earth throughout the year? Or do they just discard the data in the dark areas?

Seems like they just blank it off if it's not in direct sunlight. Probably they don't even transmit it. Look at the actual realtime image:
https://lance.modaps.eosdis.nasa.gov/realtime/

See the location of the image (red square on the small globe) covers the pole. But they don't transmit date from the visible images. However they DO transmit the Band 31 (infrared) image

And you can see the Band-31 in Worldviewer. So there's no hole. Here I've overlaid it slightly transparent over the visible light Terra image so you can see the missing daylight region.
https://worldview.earthdata.nasa.go...as=2016-10-18&ae=2016-10-27&av=3&al=undefined

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Is there a reason why none of the satellites fly directly over the top?

Youd think at least 1 satellite would have a direct path

Below are pics of orbits (night) of every satellite on the list

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Is there a reason why none of the satellites fly directly over the top?
Yes. It is described in the wikipedia article Sun-synchronous orbit.
The uniformity of Sun angle is achieved by tuning the inclination to the altitude of the orbit (details in section "Technical details") such that the extra mass near the equator causes the orbital plane of the spacecraft to precess with the desired rate: the plane of the orbit is not fixed in space relative to the distant stars, but rotates slowly about the Earth's axis. Typical sun-synchronous orbits are about 600–800 km in altitude, with periods in the 96–100 minute range, and inclinations of around 98° (i.e. slightly retrograde compared to the direction of Earth's rotation: 0° represents an equatorial orbit and 90° represents a polar orbit).[2]
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Is there a reason why none of the satellites fly directly over the top?
I think it is because it would require too much fuel to freeze the orbit as it would need constant correction. By having an inclination it allows you to freeze the orbit with only occasional corrections.

It might also improve the resolution over the outer areas, like the ice shelves, which are of much more interest than the inner area. Since it's a narrow strip you need to have a criss-crossing pattern to get full coverage. If it was a full polar orbit the bands would never cross.

Either way, there full coverage via various other satellites, planes, and people viewing the areas on a regular basis.

Yes. It is described in the wikipedia article Sun-synchronous orbit.
The uniformity of Sun angle is achieved by tuning the inclination to the altitude of the orbit (details in section "Technical details") such that the extra mass near the equator causes the orbital plane of the spacecraft to precess with the desired rate: the plane of the orbit is not fixed in space relative to the distant stars, but rotates slowly about the Earth's axis. Typical sun-synchronous orbits are about 600–800 km in altitude, with periods in the 96–100 minute range, and inclinations of around 98° (i.e. slightly retrograde compared to the direction of Earth's rotation: 0° represents an equatorial orbit and 90° represents a polar orbit).[2]
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And also in the article on polar orbits:

To retain the Sun-synchronous orbit as the Earth revolves around the Sun during the year, the orbit of the satellite must precess at the same rate, which is not possible if the satellite were to pass directly over the pole. Because of the Earth's equatorial bulge, an orbit inclined at a slight angle is subject to a torque which causes precession; an angle of about 8 degrees from the pole produces the desired precession in a 100-minute orbit.[2]
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As I understand it, it's perfectly possible to put a satellite into a precisely polar orbit, but it wouldn't be all that useful, and it would be harder to maintain.

Edit: you can find a list satellites by their orbital details here: https://www.wmo-sat.info/oscar/satellites

If you list by inclination, you can find a few (not currently in operation) with an inclination of exactly 90 degrees.

The CLARREO programme appears to be on hold and may not ever happen.

IMAGE was in operation from 2000 to 2005, and was used to study the magnetosphere. It was targeted to have an inclination of exactly 90 degrees, and achieved within 0.01 degrees of this.

The closest orbit to the poles that I can find currently appears to be the two GRACE satellites, with an inclincation of 89 degrees.

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This idea (that somehow NASA - who remember are the only people ever to launch a satellite , are hiding something at the poles) became popular for a while amongst people who are fans of the idea of a hollow Earth thanks to photos like this:

from the late 1960s. This one is from my own book of daily weather images taken by an ESSA meteorological satellite from late 1968

They see a hole, they assume magical polar entrance to a hidden Earth. The real reason is the stitching process - particularly in these early satellite photos. This is one piece of the mosaic before it is compiled into one image:

The Terra and Aqua satellites are inclined away by 8 degrees, but take images of a wide enough area that they cover the poles (assuming it's summer there). Here's yesterday's image of the South Pole
https://worldview.earthdata.nasa.go...as=2016-10-18&ae=2016-10-27&av=3&al=undefined

The North Pole looks like:
https://worldview.earthdata.nasa.go...as=2016-10-18&ae=2016-10-27&av=3&al=undefined

Not because Terra is avoiding the North Pole, but because it's winter there. Go back one month and there's less

And two Months are we are back in summer:
Hi, just come from a google search but wanted to query something about these images. Specifically the one that seems to debunk the hole, by showing the North Pole in summer with no hole.

Thing is, from what I understand, they admit fully to using an algorithm to fill in the centre. And that is clearly shown in that image at the centre where there is a jagged set of mountains around a very blank and featureless centre. Which to my mind is both very convenient but also means it also isn't quite as cleanly closed.

I'm not a blind believer either way. But some things don't quite add up on both sides and I'm keen to find fully reliable evidence one way or the other.

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Thing is, from what I understand, they admit fully to using an algorithm to fill in the centre. And that is clearly shown in that image at the centre where there is a jagged set of mountains around a very blank and featureless centre. Which to my mind is both very convenient but also means it also isn't quite as cleanly closed.
Can you explain what you mean by "jagged mountains"? There are no mountains at the North Pole, because it is just sea ice.

For example here is a random date from last year during the Arctic summertime:

You can zoom right in on the polar area and just see an unbroken expanse of ice, with no artefacts that I can see:

You can try this for yourself here: https://worldview.earthdata.nasa.go...,197119.99999999953,-406528,643071.9999999995

If you scroll through a day at a time you can see the ice ridges and areas of open water moving with the icepack, just as you would expect.

Click the timeline at the bottom to change dates.

Can you explain what you mean by "jagged mountains"? There are no mountains at the North Pole, because it is just sea ice.

I'm referring to the third picture on my post above, ("two months later we are back in summer").

As you say, in the very centre there's very little to see but to the bottom side of the centre where it moves into what looks like mountains, you can see what looks like shark teeth where the image has been repeated in something like photoshop. It's clearly not what it actually looks like, so it makes the rest hard to believe too. Somehow or other it's been 'corrected' or filled. Something they admit to doing. But that means the picture isn't true. And that leaves it open to doubts about how much they have 'corrected' or filled.

Cheers

This is made from multiple different images, each one a different pass over the North Pole. The full image is made from stitching together those images, so you get the lines where the clouds are different.

I see Mick has beaten me to it. The satellite passes over the Earth in an inclined orbit so each pass is a little bit further around the Earth.

Those get stitched together to make the full image, and, as you have noticed, the clouds move between orbital passes, so they don't match at the joins. Nothing is being "made up" or added. It's just that the way the swathes are stitched together makes them all join up at the pole, so they are more obvious - like how the paper segments covering a globe all come together at the poles.

If you zoom in and look below the clouds at the ice, you can see that the sections match up a lot better (although still not perfectly), because the ice moves much more slowly than the clouds do.

I understand what you're saying but as far as I can see the upshot remains that the image in the centre is unreliable. Are you going to tell me that "they can send someone to the moon but" not manage to stitch the images together properly? There are inevitable areas that aren't covered by the images as a result.

On the one side there are people desperate to believe there's a cover up. On the other, those desperate to believe what they're told is true. My own eyes tell me that the images don't match what's there and that there's a degree of doubt that the pictures don't assuage because I know they're not accurate representations but conveniently requiring trust for people I don't trust just because they say so.

That all said, the pictures are very helpful albeit inconclusive

I understand what you're saying but as far as I can see the upshot remains that the image in the centre is unreliable. Are you going to tell me that "they can send someone to the moon but" not manage to stitch the images together properly? There are inevitable areas that aren't covered by the images as a result.

All the areas that are in sunlight are covered. And if you look at the Band 31 (infrared) images then it's all covered.

You can just look at the original pre-stitched images.
https://lance.modaps.eosdis.nasa.gov/cgi-bin/imagery/realtime.cgi
(enter the date in the box, 8/30/2016 and press enter)
Hover over an image to see where it came from. Click for larger:

You can also view the tracks in Worldview
https://worldview.earthdata.nasa.go...3577566,175541.87930828892,1066760.0549642243

There's plenty of images that cover the pole.

You could stitch it differently, but that would just move the seams elsewhere.

So is the Earth hollow and flat at the same time?

The holes at the poles thing goes way back. This is a cover from Flying Saucers Magazine - June 1970

The idea of the holes at the poles did not originate at this time with these photos; these photos were triumphantly put forth by the publisher and editor - the infamous Ray Palmer - as proof of a long existing theory.

His involvement with the holes at the poles theory went back to the '40's and the "Shaver Mystery." It started as a series of fantasy stories set in an underground world inhabited by robots, degenerate aliens, human slaves and so forth. Eventually the setting for these stories was revealed to be "real." I can't really do justice to the Shaver Mystery in such an abbreviated form. And then there was all the cross pollination between the Shaverites and some UFO believers.

By 1970 this was all kind of old fashioned, but the lowdown is that one "theory" was that UFO's were popping up out of the holes in the poles that lead to a second earth inside of our earth. Either the UFO civilization was indigenous to this second earth or the second earth was an alien outpost, or a long cut off alien colony... you get the idea.

But the whole thing goes back much further.

https://en.wikipedia.org/wiki/John_Cleves_Symmes_Jr.

On April 10, 1818, [John Cleves] Symmes announced his Hollow Earth theory to the world, publishing his Circular No. 1.

In its original form, Symmes' Hollow Earth theory described the world as consisting of five concentric spheres, with our outer earth and its atmosphere as the largest. He visualized the Earth's crust as being approximately 1,000 miles (1,610 km) thick, with an Arctic opening about 4,000 miles (6,450 km) wide, and an Antarctic opening around 6,000 miles (9,650 km) wide. Symmes proposed that the curvature of the rim of these polar openings was gradual enough that it would be possible to actually enter the inner earth without being aware of the transition.[17] He argued that due to the centrifugal force of Earth's rotation, the Earth would be flattened at the poles, leading to a vast passage into the inner Earth.[12] Symmes' concept of polar openings connecting the Earth's surface to the inner Earth was to be his unique contribution to Hollow Earth lore.[16] Such polar openings would come to be known as "Symmes Holes" in literary Hollow Earths.

Writing in August 1817 to his stepson, Anthony Lockwood, Symmes for the first time stated that "I infer that all planets and globes are hollow".[22] But Symmes' theory was far from unprecedented. While the idea of polar openings leading into a Hollow Earth was Symmes' innovation, the concept of a Hollow Earth had an intellectual pedigree dating back to the 17th century and Edmond Halley.[23] Halley proposed his Hollow Earth theory as an explanation for the different locations of the geographic and magnetic poles of the Earth. While Halley's contemporaries found the geomagnetic data he had gathered to be of interest, his proposal of a Hollow Earth was never widely accepted.

Symmes Hole, from Harper's New Monthly Magazine, 1882

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This idea (that somehow NASA - who remember are the only people ever to launch a satellite , are hiding something at the poles) became popular for a while amongst people who are fans of the idea of a hollow Earth thanks to photos like this:

from the late 1960s. This one is from my own book of daily weather images taken by an ESSA meteorological satellite from late 1968

They see a hole, they assume magical polar entrance to a hidden Earth. The real reason is the stitching process - particularly in these early satellite photos. This is one piece of the mosaic before it is compiled into one image:

Dear One Big Monkey, What is the name of your book pictured here with the ESSA earth photos? I'd really love to locate and own this book. (impossible as it may be)

Apologies for the delay in replying.

The book is a hard copy of the Key to Meteorological Records Documentation No 5.320

Catalog of meteorological satellite data - ESSA 7 television cloud photography : October 1 - December 31, 1968

It's one of a regular series of summary volumes from ESSA satellites. This particular volume was published by the US Dept of Commerce in 1970. available to the public for the princely sum of \$2. My copy was from a second hand store (online), and was originally in the library of Miami-Dade College.

This is a digital version of the book:

ftp://ftp.library.noaa.gov/docs.lib/htdocs/rescue/TIROS/QC8795C381970ESSA3-5-7pt2.pdf