Tuesday evening the crescent Moon grazed the Pleiades star cluster low in the west after dark in what was a lovely sight to naked eyes and dazzling in binoculars. Hope you saw it.

As it passed in front of some of the stars, it seemed as if the huge Moon swallowed the tiny stars.

Such occurrences provide excellent examples of how misleading appearances can be, especially regarding sizes and distances in the cosmos. It's easy to see how our ancient ancestors formed what we now know to be such wrong conceptions of the universe.

There's no question the sky looks big, and the Sun, Moon, stars and other night sky objects look far away. But only in recent decades have we come to realize just how big and how far away.

One of the largest appearing objects, the Moon, is really tiny with its 2,159-mile diameter being less than the width of the U.S. And orbiting Earth at an a average distance of only 239,000 miles, it's little more than an extension of Earth.

And while the Sun and Moon appear the same size, that too is deceiving. The Sun's diameter of 864,000 miles is 400 times that of the Moon (and over 100 times Earth's diameter). The Sun and Moon look of equal size because, by coincidence, the Sun's average distance of 93 million miles happens to be 400 times that of the Moon's average distance.

But even all these sizes and distances pale in comparison to those of the Pleiades. Each of those 100 or so "tiny" stars is a sun, many much larger than our own. And their distance? How about 2.4 quadrillion miles (add 14 zeros!). Such a large number is so cumbersome astronomers use a unit of measure called a light year - the distance light travels in a year (5.9 trillion miles). So really the Pleiades are only 407 light years away - relatively nearby, cosmically speaking.

It quickly gets far more mind-boggling. Our Milky Way galaxy, 100,000 light years in diameter, is but one of countless billions of galaxies, most of which are thousands to millions of light years distant from each other. So while seeing the Moon graze the Pleiades is aesthetically beautiful, it gives no clue as to the true enormity of our universe.

- Sky Calendar.

* 11 Fri. evening: The Moon is near Mars in the early evening, and pulls within one moonwidth before they set around 2 a.m.

* 12 Sat.: The Moon is at 1st quarter.

* 14 Mon. evening: The Moon is to the right of Saturn.

* 15 Tue. evening: The Moon is to Saturn's lower left with the less-bright star Regulus to the planet's right.

* 20 Sun.: The full Moon is called Grass Moon and Egg Moon.

* 22 Tue. morning: Lyrid meteor shower peaks but with bright Moon interference.

* 23 Wed. morning: The Moon is to the right of Antares.

- Naked-eye Planets. (The Sun, Moon and planets rise in the east and set in the west due to Earth's west-to-east rotation.) Evening: Mars is overhead with Saturn high in the southeast. Morning: Brilliant Venus hovers near the eastern horizon shortly before sunrise; Jupiter is the brightest object higher in the southeast.

- Eclipse Countdown. It's now only 16 years until the April 8, 2024, total eclipse of the Sun passes directly over the heart of Texas. Live healthily so you can join me in watching it.

- Astro Milestones. Apr. 12 is the 47th anniversary of Yuri Gagarin's 1961 historic 108-minute orbital flight around Earth - an early Space Age milestone. Astronauts now spend months in Earth orbit in the International Space Station.