Q: My brother and I always liked looking at the stars. In a recent story, it said that a man looked up and saw a supernova explode. Doesn’t that mean it actually exploded 166,000 years ago or about when modern homo sapiens were just starting to evolve in Africa and the light is just now getting here? The story doesn’t say. Also, we usually can’t see possible supernovae with the unaided eye. Well, Hubble and Planck technology was not here 50 years ago, which prompts this question: If one exploded 100 years ago we here on the ground wouldn’t know it. But could the Hubble telescope pick it up earlier and tell us it’s coming?
Joe Fontana, of Roxana
A: Yes it could, but you’d better be ready to react pretty darn fast.
Because that groundbreaking telescope is orbiting the Earth, it would pick up light from an exploding star before those rays traveled the final 350 or so miles down to our eyes here on terra firma. But since light travels at approximately 186,000 miles a second, your Hubble advance alert would be only a fraction of a millisecond (350 divided by 186,000), Kyle Stumbaugh, a science instructor and Astronomy Club adviser at Southwestern Illinois College in Belleville, explained.
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“That’s about it,” he said. “So timewise it’s not seeing much different than from what we see. There’s not much difference in that at all.”
Your hypothesis to your first question is correct. As I’ve noted, light travels fast but when you consider the vast distances in space (bill-yuns and bill-yuns of miles, as the late, great Carl Sagan would have said), it’s almost like watching a snail crawl down the sidewalk, comparatively speaking. That’s why the distance of most objects from Earth is measured in light-years — the distance light travels in one year. That’s nearly 6 trillion miles. So even the nearest star (outside of our sun) — Proxima Centauri — is roughly 25 trillion miles distant or about 4.22 light years.
As you note, such distances are hard to wrap your head around. For example, if the sun were to explode at this very instant, nobody on Earth would see it for about eight and a half minutes because that’s how long it would take the light to travel the roughly 93 million miles here. And the Hubble would be of no help warning us of the impending disaster (not that it would do us any good, anyway).
Now, the Hubble certainly has been a technological and scientific marvel because, like a camera with a mind-blowing aperture, it allows us to see distant objects far too dark or faint to be seen with the human eye.
For example, way back in about 150 B.C., the ancient Greek astronomer Hipparchus, who is usually credited for developing trigonometry, also is believed to be the first to divide the stars of the night sky into six classes based on brightness. The brightest stars were said to be of first magnitude followed by second magnitude, etc. This meant that the faintest stars that the unaided eye could make out (even without the light pollution of modern society) would be magnitude 6. The Hubble allows us to see stars that would be rated roughly magnitude 17, Stumbaugh said, so you can see how much more of the universe it allows us to see.
But while it can photograph objects far more distant than Hipparchus could ever dream of seeing, it does not see those objects at any later stage of development than we would with our naked eye if we would be able to see them. In other words, just like your example, if a star is a billion light years away, the Hubble would see the star as we would, only a fraction of a second sooner.
So, sometimes even science has its limitations, but it also offers eye-popping wonders as it will on Aug. 21 when the St. Louis area will be treated to its first total solar eclipse since — are you ready for this? — 1442. And to fuel your interest and get you ready, two groups will offer free educational seminars next month.
First up, Angela Speck, director of astronomy at the University of Missouri, will discuss “Eclipse of a Generation: Don’t Get Left Out of the Dark!” from 7-8 p.m. June 1 at the McDonnell Planetarium in Forest Park. Drinks and hors d’oeuvres will be available and a free pair of eclipse-viewing glasses will be given away while supplies last. For more information, call 573-884-4482.
Then, two weeks later, the St. Louis Eclipse Task Force and St. Louis Astronomical Society will offer two days of talks and activities at the Greensfelder Recreation Complex at Queeny Park.
The event opens at 6 p.m. June 16 with a night featuring a free expert panel that will include Speck, NASA solar scientist Mitzi Adams and Mike Reynolds, professor of astronomy at Florida State. The five-member panel discussion will start at 7:30 but those attending will get the first chance to see 20,000 square feet of vendor exhibits.
The expo continues from 10 a.m. to 5 p.m. June 17 with exhibits, children’s activities, workshops and more speakers, including former KSDK meteorologist Mike Roberts as emcee. Admission both days is free, but you should get advance tickets at www.eclipseexpo.org. In addition, Friday’s program is limited to 500 and, at last check, only about 125 remain. Those attending will receive the special glasses while supplies last.
If it rains this August, when will St. Louis see its next total solar eclipse?
Answer to Friday’s trivia: Credit a friend for making a Facebook note of driving on the War on Terror Memorial Highway while on a recent trip that took him through Alabama. “What feeling is it even meant to evoke?” he wondered about the name in his post. I’ll tell you: It’s meant to make you remember everyone who has died in the war on terror since 9/11, says Mary Nell Winslow, of the Alabama Gold Star Mothers. Her organization noticed signs memorializing other wars already up on Alabama interstates, so members thought it was high time to honor those who have paid the ultimate sacrifice since that tragic day in 2001. So, in May 2014, signs were unveiled to designate Interstate 65 between mile markers 212 and 219 in Chilton County, Alabama, as the War on Terror Memorial Highway.