JWST

that's a lot of moving parts

Today we will talk about audacious astronomy and the James Webb Space Telescope. For the mathematically inclined, we need this thing to sit in a particular spot. The telescope has only 63 gallons of fuel to make this whole show go for the next ten plus years. A wonderful time to be alive.

The Inspiration

If you missed the first part of this post, it began with “I See“. If you previously read “I See”, you know that the topic is all about telescopes. Until the 1930s, all of our telescopes were visible-light telescopes and they were, of course, on Earth. The discoveries of Edwin Hubble and others led to new telescopes outside of the visible range. We have even managed to place a few beyond Earth’s atmosphere. Wow! Today’s post runs a bit long so skip the photo captions to save some time!

Most all of these posts make me so thankful that we have these large frontal lobes. Our original equipment eyes can only see things in the NARROWEST of wavelengths. The visible spectrum is just a glimpse of all that is happening. Our vision is SO LIMITED that it is hard to present a workable analogy. We can hear through about 15 ranges of power from the quietest sound to an ear-damaging level like a jet aircraft. The light spectrum shown in the electromagnetic spectrum covers about 32 ranges of the light spectrum from radio waves to gamma rays. Our eyes cannot see even one of the 32 ranges. A fair analogy is if our ears were as “bad” as our eyes, we wouldn’t even be able to hear anything except perhaps a handful of very similar bird chirps. It is the wonder of our minds and the drive to explore that has unlocked the rest of all there is to “see”. None of this is to sell humans short. Our vision is fantastic in many ways. A handful of animals can sense the ultraviolet range and infrared ranges. Our human eye is impressive but our human ingenuity to create technology to do this for us is a better solution.

We’ve managed to exploit the whole spectrum in the last 140 years. Some of the discovery is credited to a man named Heinrich Hertz. The next time you watch some television or look at your phone, the crisp image you see has to do with how FREQUENTLY the screen updates. Lots of them work at 60 Hz (cycles per second). The frequency of light measurement is named after Mr. Hertz.

The Setup

Here is a detailed description of all sorts of telescopes and their applicability. Some telescopes took the next step and were stationed outside the atmosphere. The Hubble Telescope (HST) is the most famous example (about 350 miles up orbiting once every 97 minutes) but there are others. For me, that is like driving to Madison WI. So much of our modern world is due to these efforts to seek the new. Space exploration is no exception. It requires SO MUCH effort and fuel to place anything in space. Placing objects in orbit has the advantage that the forces of nature work for us. By taking advantage of orbits, we can minimize fuel requirements, and hence space objects can remain viable for a longer time.

The Details

A French mathematician, Joseph LaGrange provided an interesting computation related not to orbits but rather to two different bodies and their relative sizes and distances apart. It refers to the “multiple object problem”. For humankind, the two object problem in our case often involves the Sun and the Earth and sometimes the Moon. An object like the JWST will sit in a spot well beyond Earth's orbit. Nevertheless, Earth will still exert some gravitational pull on the craft. Likewise, because of the immensity of the Sun, the spacecraft will also be affected by the gravitation of the Sun. If you are a “space nerd” like me, here is a great website that tracks the mission. It includes a tracker for distance. If you check it today you might even see the sunshade starting to deploy in the coming days. Once the sunshield is deployed the difference in temperature between the hot and cold side will be impressive. Slowly but surely the temperature of the telescope instruments can begin cooling to the extreme lows needed for them to work. Much more difficult than starting your car on a cold morning in Minnesota!

I’ve had two cars that made it to the moon, that is, they successfully traveled the distance to the Moon (about 239K miles). When I think about how unreliable cars used to be, we have come a long way! Both of mine made it without engine or transmission failure. I will have to be satisfied with that. I do not expect to have a car make it to the L2 LaGrange point (one million miles). By the time you read this, we will have blown well past the moon! The Dad in me thinks “We’re making good time”.

The L2 LaGrange point is special because it balances gravity and centripetal force. The spot chosen will consistently remain with the Earth between the telescope and the Sun. From such a vantage point, the JWST will be able to peer outward into the universe without the light of our sun occluding the view. A bit of light will seep through but the shielding will absorb and redirect the input light. Small adjustments in the placement of the JWST will be accomplished with a modest amount of fuel. The hope is that a way to refuel the telescope can be developed in the years ahead to extend the life of the mission. The JWST should be able to operate effectively for ten years if all goes well with the hope of refueling to extend its lifetime. Remember that Hubble is about 350 miles away. JWST will be about one million miles away. Its orbit will be elliptical around the L2 point remaining mostly behind the earth but just grabbing a bit of light to power itself at the edges. JWST will transit around the Sun just like the Earth once per year. If the telescope were to become exposed directly to the Sun, it would likely damage the JWST beyond repair so blocking the Sun is a very large priority.

LaGrange worked out an interesting bit of mathematics based on unique positions where gravitational forces and orbital forces balance each other out. These positions are designated as L1 through L5. L2 is the ideal location from which to view the greater universe and is about 1 million miles away, about four times the distance to the moon. This is the location of certain space-based observation instruments. The James Webb Space Telescope (JWST) will be placed in this location. Once it is placed, it cannot be reached for service, unlike the Hubble Telescope which had five service missions. This makes the James Webb Telescope orders of magnitude more complex of a mission. The significance of L2 is that the gravity of the Earth and the sun are in balance and the JWST will always remain with the Earth in between largely blocking the sun.

We theorize the universe is 14.5 billion years old. After 2000 years of human effort and theorizing about the universe, on Christmas morning, humans launched a vehicle that allows us to see what the world was like 13.5 billion years ago at the very BEGINNING of the birth of the stars. The telescope is tuned to be able to discern the light of these earliest stars. The JWST will also be the tool of choice for detailed observation of the planets in the Milky Way galaxy that appear to be the best prospects for the emergence of life.

I am so excited about these efforts. I realize that while my enthusiasm may show, I just defer to the experts. I am sure that if you watch these videos, you will begin to follow the JWST mission. Over the next six months, the telescope will journey to L2, deploy and unfold, calibrate itself, and then begin to tune itself for sending photos back to Earth. The complexity of the mission, the NASA gamble of 25% of its budget, and a program now fourteen years beyond its original schedule is a very large bet. The breadth and audacity of the plan are inspiring. In one of the videos, a woman involved in planet analysis says “What makes us human is to be curious, and to push boundaries, and to explore, and increase our understanding of the universe. JWST is the next piece of that puzzle.”

I think it is always worthwhile to have perspective when it involves amazing achievements. Here is my favorite. The analogy here is to equate our ability to see something on the moon compared to what JWST can see as the first stars are forming after the Big Bang. Imagine we plugged in a nightlight on the moon. Typically these output about five watts. Now imagine that the nightlight was set to 1/20th power or about 0.25 watts. Being able to see that nightlight from Earth is the same as JWST's vision out to the edge of the universe. It will be able to allow us to see through the dust clouds of early galaxies.

For those who don’t see this as a worthwhile priority, it is useful to realize that each day we wait, there will be LESS FOR US to see. Alas, the universe is expanding and these most faraway galaxies and stars are traveling in the opposite direction at speeds beyond the speed of light! Each moment of delay caps the outer limit of what we will EVER be able to see. Incidentally, Americans spend about four times as much on cigarettes as we do on NASA. An industry close in size is the adult diaper industry. Food for thought.

Finally, just like another magical item here on earth, an MRI machine, it will be able to measure the vibration (resonance) of the elements of the universe and hence be able to tell us what these most out-of-the-way objects in the universe are made of. That means we will be able to characterize all of the spots that likely sustain life. I think that if that moment arrives soon it will be our generation’s “Copernicus moment”. I expect that Facebook/Meta will do its best to litter our primitive lizard brains with nonsense to combat such profundity with conspiracy. I hope that people will take the time to set the nonsense aside, reject the conspiracy, and celebrate this latest achievement of those of us who live on the “pale blue dot” that Carl Sagan waxed poetically all those years ago on Cosmos.

These videos which I found while treadmilling are some of the best I’ve watched. The mission begins on the morning of Christmas Day in French Guiana.

Lots of good music about space. This was a decent default choice. Here’s a second song about one of our primary goals in building telescopes these days. Today, I celebrated 22,280 days on the rock.