Geosynchronous vs Geostationary Orbits

Geostationary OrbitIn this morning’s Anniversary Post, I talked about the first geostationary communications satellite, Syncom 3. And I briefly discussed the difference between a geostationary satellite and a geosynchronous satellite. I thought it would be interesting to discuss it, because it is one of those many astronomical concepts that are murky to most people. Even though a geostationary orbit is a special case of a geosynchronous one, it makes most sense to start with the special case.

The main thing you need to understand in all of these orbits is that the satellite moves around the Earth so that it is always at the same longitude. It is thus easiest to think about a satellite that orbits along the equator. You can see this in the animated gif above. What this means is that the angular velocity of the satellite is the same as the rotational rate (also the angular velocity) of the Earth. In this case, the satellite would always be over the same exact spot on the earth. This should all be pretty straightforward — especially with the animation.

But what if you wanted to put a satellite right over San Francisco, which is at 37.8° N latitude and 122.4° W longitude? That’s not possible. Satellites have to orbit around the Earth’s center of mass, so their orbit must trace out a great circle on the earth — like the equator, but rotated in any direction from where it is. It would thus be possible to set up a satellite that orbits right at 122.4° W longitude, but its latitude would change over the course of the day, moving down into the southern hemisphere and then back up to the north, being directly over San Francisco at the same time the following day.

Since a general geosynchronous satellite is not visible at all points along its arc for all inclinations, geostationary satellites are more useful. This is especially true of satellite dishes. If a geosynchronous satellite were used — even from a very low latitude — the dish would need to be constantly adjusted to point to the satellite. This is possible, of course. The last major project I worked on did just that: using a 900 MHz (broad but low bandwidth) signal to fix the location of the object, so that a 2.4 GHz (narrow but high bandwidth) antenna could be pointed at the object. Thus we were able to stream realtime video from an airplane to the ground. But that’s pretty involved, and as you’ve probably noticed: home antennas just point in one direction.

That’s the difference between geosynchronous and geostationary orbits. I think that a lot of the time, people think that anything can be done in space. But that is not true at all. We just put those satellites up there and let gravity work its magic. That’s why the Syncom satellites are still spinning around us even after fifty years.

“Only Positive Attitudes Allowed Beyond This Point”

Only Positive Attitudes Allowed Beyond This PointI’ve come across this poster slogan in a number of schools, and each time I see it, my heart sinks. Its effect isn’t to create a positive atmosphere but to serve notice that the expression of negative feelings is prohibited: “Have a nice day… or else.” It’s a sentiment that’s informative mostly for what it tells us about the needs of the person who put up the poster. It might as well say “My Mental Health Is So Precarious That I Need All of You to Pretend You’re Happy.”

Kids don’t require a classroom that’s relentlessly upbeat; they require a place where it’s safe to express whatever they’re feeling, even if at the moment that happens to be sadness or fear or anger. Bad feelings don’t vanish in an environment of mandatory cheer — they just get swept under the rug where people end up tripping over them, so to speak. Furthermore, students’ “negativity” may be an entirely apt response to an unfair rule, an authoritarian environment, or a series of tasks that seem pointless. To focus on students’ emotions in order to manufacture a positive climate (or in the name of promoting “self-regulation” skills) is to pretend that the problem lies exclusively with their responses rather than with what we may have done that elicited them.

—Alfie Kohn
Cheerful to a Fault

Conservative Ethos Among Moderate Liberals

Corey RobinI have long felt in an odd place politically. I am a liberal — even a socialist, although I think the word doesn’t mean much in an American political context. Yet I consider myself deeply conservative in a personal way. I’m not keen on change. I do value (good) tradition. What I’m not is hateful and exclusionary. And when I look backwards, it is not to see some static past, but rather to see the process. I am very interested in taking what has worked in the past and using it today. But I’m not at all interested in fetishizing the past.

But that is one thing about my conservatism: I think the whole process of not seeing the past correctly dishonors it. Here in America, there is far too much facile patriotism. People are patriotic in the same way that football fans cheer for the home team. Listening to most people talk about the country, the furthest they will go is to admit that “mistakes were made” in the past. They are of the mentality of, “My country, right or wrong.” But if you look at the actual Carl Schurz quote, it is, “My country, right or wrong; if right, to be kept right; and if wrong, to be set right.” That seems to me to be the most basic kind of conservatism.

Corey Robin wrote a very interesting article about this question earlier this month, We Have the Left and Right All Wrong. Let me note that of course conservatives don’t look back. I’ve written about this a lot in the past: conservative thinkers only have a shelf life of about a generation, because after that, the vileness of their thinking becomes clear. As Robin noted, “In Burke’s case, it was aristocrats over commoners; in the nineteenth and twentieth centuries, it would be masters over slaves, employers over employees, husbands and men over women and wives.”

One question that a lot of us liberals ask is why it is that workers rebelled against the power elite a century and more ago, but that they are largely complacent now. Robin claims it is because workers then had a memory of the way that life was before industrialization. Here’s a shocking bit of data: in 1820, 80% of all workers were self-employed; 120 years later, 80% worked for someone else. And nothing has changed since then. Don’t think that the people working for Uber are really self-employed. They are just employees by another name. Regardless, before industrialization, workers had more control of their lives. Remembering that was critical to liberal organizing at the end of the 19th century.

The greatest success that the power elite have had is in making everyone think that the current economic system we have is the only one possible. And this is how we get the New Democrats and neoliberalism. It is based on the idea that we can only tinker with the existing system. It’s a very dangerous mentality. If you truly think there is no other system, you don’t work on other systems. And you are stuck. As Robin wrote, “Capitalism rests upon repeated acts of forgetting; a robust anti-capitalism asks us to remember.”

When modern conservatives think about the past, it isn’t history or even memory — it is nostalgia. We see this in the Republican presidential debates. There is a constant hearkening back to when America was “strong” and “respected” and above all “authentic.” All of these ideas mean everything and thus nothing. They ultimately work to the benefit of an eternal now. Liberals are the ones who see the past and mine it for what was good and try to develop a better future. We are the ones who value history — we are the true conservatives.

Labour Party Much Like the New Democrats

Jeremy CorbynIt is looking more and more like Jeremy Corbyn will be elected to head the UK Labour Party. I’ve written about it before in the the context of the screwed up UK media. But the truth is that the media are screwed up only because the Labour Party leadership is so screwed up. Let me explain.

Corbyn is an old fashioned leftist — you know, the kind who actually stands for leftist values. He has never had much power in the party. And the way the Labour Party elects leaders, he normally wouldn’t even be in the running. In order to be on the ballot, a candidate must be nominated by 35 MPs. Well, Corbyn did not get that. But at the last minute, a number of MPs changed their votes, because they wanted him in the election to have a wide variety of opinions.

These same MPs were not planning to support Corbyn in the election. And here is the key thing: they never dreamed that Corbyn would actually win. Now we are seeing lot of coverage claiming that the Labour Party membership has moved to the left. But this is poppycock. What really happened is exactly what’s happened in the Democratic Party: the voters have stayed where they were while the party establishment have gotten more and more conservative.

It’s interesting to compare this to the Republican Party. In that case, the base of the party has gotten more conservative while the party establishment has tried (futilely) to hold it’s already extremely conservative ground. I only mention this so that no one mistakes what’s going on with the two liberal parties with what continues to happen with the Republicans. It isn’t the same — at all.

I suspect that the Labour Party voters were happy enough with the establishment as long as it won elections. But if not, what is the point? “Not as bad as the Tories” really isn’t much of a rallying cry. And let’s be honest, that’s all that Labour has offer these ten years or so. But I don’t expect to the Labour Party establishment to accept this. As it is, they are now talking about how Corbyn’s support is the result of Tories sneaking into the party to destroy it. The establishment just doesn’t get it.

It’s even worse than this. Simon Wren-Lewis has reported that many of the top people in the Labour Party have refused to serve under Corbyn if he is elected. But that’s nonsense. “If, following a Corbyn win, the party united around him in exchange for Corbyn parking some of his less popular policy positions, Labour could once again become an effective opposition. If instead his leadership is accompanied by constant public division within the party, there is a danger that this will overshadow everything else.” But I suspect there will just be more infighting, because what the party has become is too divorced from what its voters actually believe in.

Of course, it is far worse in the United States. At least there, the parties aren’t crazy. Here, we have hugely popular ideas — like raising the minimum wage — that are only starting to get traction in one party and are completely off the table in the other. But the whole thing makes me wonder about democracy in the world. Does the will of the people matter anymore? Or will the political parties always gather around the desires of the power elite? I’m afraid it is the latter.

Morning Music: Les Bourgeois

Les BourgeoisWhen it comes to spirituality in the sense that I mean it, I could pick almost any song by Jacques Brel. That’s what I love about him: his songs are all about real people and their relationships. But the song that really sticks out to me is “Les Bourgeois” off the album of the same name. The singer tells the story of his friends and him mocking the older notaries, “The older they get, the stupider they become.” But in the last verse, the young men are now older — middle class, now notaries themselves, drinking in the bourgeois bar. And the new generation of young men mock them with the same refrain.

What’s interesting is that there is some wisdom gained — even if it is drowned by resentment. But the men are still who they always were. Jojo is still Voltaire in his mind; Pierre is still Casanova; and the narrator just as narcissistic as ever. There is a continuity of life — a cycle. But we only appreciate it as we look back. If we lived to be 500, we would look back wryly at the silliness of ourselves in our 90s. We never arrive at enlightenment. We seek it. Maybe we even move toward it. But enlightenment is as elusive as the universe itself.

Anniversary Post: Voyager 2

Voyager 2On this day in 1977, Voyager 2 was launched from Earth. It was actually launched before Voyager 1 — you know astronomers. Well actually, because of the route it took, it actually ended up visiting Jupiter and Saturn afterwards. And since the only thing that most people care about are the pretty pictures (Not that I’m complaining!) it isn’t necessarily a bad thing.

The remarkable thing is that Voyager 2 — now in space for 38 years — is still operating. In the next couple of years, it is expected to start sending data about the density and temperature in the interstellar region. It is currently over 100 AU (one AU is the distance from the earth to the sun). That’s over twice the distance to Pluto at Pluto’s greatest distance from the sun. It is believed that Voyager 2 will continue sending data back to earth until 2025.

I had always thought that Voyager 2 was the spacecraft that was repaired by aliens and made self-aware in Star Trek: The Motion Picture. But that’s not true. It was actually Voyager 6. If you don’t remember that spacecraft, it is probably because it never existed. In the universe of the film, NASA launched it but then lost sight of it. Still: really not a bad film at all!

Happy anniversary Voyager 2!