Fifty-seven years ago this week, Mariner 4 captured the “first photos humans had ever seen of another world” as it flew within 6,200 miles of Mars.
Earlier this week, NASA released the first images from the James Webb Space Telescope, revealing galaxies as they appeared 13 billion years ago. As David Von Drehle wrote, this is “the closest humans have yet come to glimpsing the true dimensions and inner workings of the universe.”
We’ve come a long way, baby.
On 14 July 1965, Mariner 4 snapped 21 black-and-white photos of the Red Planet that it sent back to Earth the next day.
After the pictures came back, they showed no canals or any obvious signs of life at all. Although blurry by today’s standards, the images were clear enough to reveal a heavily cratered surface. Scientists said it appeared Mars was more similar to the moon than to Earth.
“Man’s first close-up look at Mars had revealed the scientifically startling fact that at least part of its surface is covered with large craters,” NASA stated when it released the pictures.
In 1965, the space program was high priority news, as evidenced by its front page prominence in the New York Times.
In 2022, Webb merited a photo below the fold. The story, much deeper in the paper (A18).
Mars is the fourth planet from the sun and the second-smallest planet in the solar system. (The Earth is the third planet.) The closest the two planets have ever been is 34.8 million miles (56 million km). The furtherest apart: ~250 million miles (401 million km). The average distance between Earth and Mars is 140 million miles (225 million km).
- For context, the Webb telescope sits in orbit about 1 million miles from Earth. This is “much farther from Earth than any human has traveled.”
Mars and Earth orbit around a star (the sun) and are located in the Milky Way galaxy, which contains 100 billion to 400 billion stars.
- The Webb telescope is showing us “previously obscured areas of star birth” in our own galaxy, about 7,600 light-years away in the Carina Nebula. Carina is one of the Milky Way’s largest star-forming regions, and Webb is revealing “hundreds of previously hidden stars.”
The initial Webb photo revealed light from galaxies that “originated more than 13 billion years ago.”
Astronomers theorize that the most distant, earliest stars may be unlike the stars we see today. The first stars were composed of pure hydrogen and helium left over from the Big Bang, and they could grow far more massive than the sun — and then collapse quickly and violently into supermassive black holes of the kind that now populate the centers of most galaxies.
Contextualizing a billion
In 2004, I tried to contextualize the federal budget. As I wrote then, “most of us know that [numbers like a billion] are big, we just don’t know how to think of them in the context of our own lives.”
First, we have to clarify that we’re using the US system of numbers, not the British system (short scale v long scale). If we’re talking about things relating to the US political system, we are using the US system. Here’s the math:
1 Thousand 1,000 103 1 Million 1,000,000 106 1 Billion 1,000,000,000 109 1 Trillion 1,000,000,000,000 1012 1 Quadrillion 1,000,000,000,000,000 1015 1 Quintillion 1,000,000,000,000,000,000 1018
The chart, however accurate, doesn’t put the number “a billion” — one thousand million — into perspective.
Light travels at 983,571,056 feet (299,792,458 meters) per second. A light year is approximately 6 trillion miles (9.7 trillion kilometers). That’s six thousand billion.
The earth is about 8,000 miles wide (diameter), and the sun is about 800,000 miles wide (not quite a million). The Sun is 93 million miles away, so sunlight takes 8 minutes and 20 seconds on average to get here.
If you spent eight solid hours each day counting off the seconds, every day of the year without a break, starting at age 5, you would need to live almost to age 100 to reach 1 billion. In 100 such lifetimes, a person might count the stars of this single galaxy — one of thousands in a speck of the universe.
An awe-inspiring observation
According to the Teacher’s Guide to the Universe(opens in new tab) from Princeton University, the distance between Earth and Mars was first determined by Giovanni Cassini in 1672 using the parallax method.
Cassini achieved this by sending his fellow astronomer Jean Richer to French Guiana to carry out measurements while he remained in Paris. They took measurements of the position of Mars and triangulated those measurements with the known distance between Paris and French Guiana. Cassini’s calculation was only off by 7% compared to today’s more accurate measurements.
#scitech, #space (175/365)
📷 NYT time machine
Daily posts, 2022-2023