The wonder of the universe

December 22, 2010


Tuesday morning, I rose at 2 A.M. and stood for an hour in the freezing cold to watch a total eclipse of the full moon, occurring on a solstice: a conjunction that last occurred in 1638, and won’t occur again until 2094. Standing there, I wondered if this exceptional moonglow would give me a superpower — nothing to report yet. The sense of awe I felt right away.

The more astronomers look out into the universe, the more vast and majestic it is understood to be. As the holidays arrive, and the year comes to a close, it is well to ponder this.

Many generations ago, our ancestors gazing up at constellations and eclipses believed the cosmos bounded by such stars as could be seen unaided by the eye. Just a century ago, even after people considered themselves advanced owing to developments like powered flight, it was not known that any other galaxies existed. Our Milky Way was considered the totality of creation.

In 1923, the existence of galaxies beyond the Milky Way was proven. Initial estimates were that there might be as many as a few dozen additional galaxies — a number then viewed as stunning. The latest estimate, from the Sloan Digital Sky Survey, is 100 billion galaxies. The count is expected to rise.

Star estimates have risen in concert. A century ago, even the best-informed believed the Milky Way contained perhaps a few million stars. By the 1960s, astronomers contended the Milky Way held a billion stars, a number many found hard to believe. By the 1980s, the estimate had grown to 40 billion stars. Today it’s thought the Milky Way contains at least 90 billion stars and perhaps as many as 400 billion. Many other galaxies are likely to contain similar numbers.

Recently, researchers led by Yale University cosmologists proposed there exists at least three times as many stars as previously thought. The Yale estimate is 200 sextillion stars, a 2 followed by 23 zeroes.

In his 1988 book Coming of Age in the Milky Way, the science writer Timothy Ferris supposed there were so many stars that to spend one second contemplating each star in creation would require as long as the universe has existed. The star count has shot up so much just since 1988 that at 200 sextillion, you would need to contemplate a million stars per second, for as long as the cosmos has been here, to contemplate them all.

And stars are still forming, some right in our neighborhood. This active star-forming region is about 170,000 light-years from Earth, incomprehensible distance to us but not far in cosmic terms. This star-forming region is dense with very large, blue stars — the kind that may have dominated the early universe — meaning it’s a young star-forming region that has only “recently” become a stellar nursery. If the extremely bright star-forming region shown at the second link were inside our Milky Way, it would cast shadows at night, like a full moon.

Large numbers of new stars are forming as close to us as the Orion Nebula, which is 1,300 light-years away, “nearby” in the galactic sense.

There is a reasonable body of evidence that the cosmos came into being about 14 billion years ago, during a Big Bang or some kind of singular event. The universe is 14 billion years old — and stars are still forming.

Compared to us, the cosmos is unimaginably old. Compared to itself, creation glistens with the dew of morning.


Current evidence suggests the universe may continue, in roughly its current form, for at least hundreds of billions more years: which, to us, might as well be eternity. The universe may well exist forever, though evolving into a form with features that would seem strange, such as the deaths of hot stars and galaxies so far apart they would lose the ability to see each other. But that would happen over trillions of years, a time-scale that can’t be considered in any common-sense way.

This atlas offers a modest impression of cosmic scale, from our galaxy to the visible boundary of existence. Try clicking on the Virgo Supercluster, the suburb of galaxies in which is Milky Way is situated. Bear in mind that each tiny dot on that map represents 20 billion to 400 billion stars. If one star system in a thousand contains a planet similar to Earth, the number of Earthlike worlds will be in the billions. And that’s just “nearby.”

Are researchers wrong, and overestimating the magnitude and age of the universe? Perhaps. Many beliefs now asserted by top scientists, and received as advanced rationalism, may in light of future knowledge be scoffed at as superstition. That’s been the pattern of the past.

But it is as likely that contemporary estimates understate creation. There may be still more galaxies beyond the visible universe; other universes in other dimensions; some energy-adding process by which our cosmos never runs down. The firmament, and physics, may have majestic basic properties we haven’t even guessed at yet.

The magnitude of the universe might make you feel small — but should make you feel important. Even if we are short-lived little blips in an extremely long-lived enormous cosmos, life grants the cosmos meaning.

If we evolved on a wholly natural basis, who can say where evolution, and our own thinking, may take us? If there is a higher intelligence behind the universe, who can say what may be in store? In either event, even in a firmament of 100 billion galaxies, it is life that invests the cosmic enterprise with meaning.

Look up at that unfathomably large universe on some clear, dark night. Stare at the stars in wonder. They are staring back at you, also in wonder.

Happy holidays.

Photo captions:
Top: A supernova within the galaxy M100, that may contain the youngest known black hole in our cosmic neighborhood, is seen in this composite image. REUTERS/Chandra X-ray Observatory Center/Handout
Bottom: The Moon is engulfed in the Earth’s shadow as it nears the peak of a rare winter solstice total lunar eclipse as viewed through a telescope from Palm Beach Gardens December 21, 2010. REUTERS/Doug Murray

One comment

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[…] year as the holidays approached, I reviewed the state of understanding of the size and age of the cosmos. This year for the holidays, the topic is what science knows (or thinks it knows) about some […]

Posted by Really, really big questions | Gregg Easterbrook | Report as abusive

No wonder religious or quasi-religious politicians think the world is a bit older than 6000 years. Almost all, believers in Jesus, would be in a quandry. Any being more than 2000 plus years away would not know of the arrival of Jesus. There would have to be a nearly infinite amount of Jesuses to cover all the territory. Probably an easy trick for a Supreme Being though.

Posted by kiprave | Report as abusive