Everywhere You Look The Lights Are Going Out

My childhood hero Sherlock Holmes once commented in the story entitled “Silver Blaze” about reports of a barking dog at a crime scene: “Is there any point to which you would wish to draw my attention?” “To the curious incident of the dog in the night-time.” “The dog did nothing in the night-time.” “That was the curious incident,” remarked Sherlock Holmes. The point being, sometimes it’s the absence of something that is of interest.

Astronomy is all about gathering photons of light from space, and this week there have been several interesting stories about The Photons That Didn’t Bark…er, Aren’t There. First off, this is National Dark Sky week, a time to raise awareness about light pollution. Anybody who’s gone out into the deserts of New Mexico as I have and has seen the Milky Way from there will tell you our entire civilization is losing something precious by not being able to see the stars as all of our ancestors did.

Looking at planets instead of stars, the Hubble Space Telescope this week failed to find photons from an expected moon around newly-discovered Senda, a Pluto-sized object out beyond Pluto. (The now-missing mystery moon of Senda marks a major difference between it and Pluto, which has a moon of its own named Charon that is not to be confused with Chiron, which is yet ANOTHER planetoid discovered out beyond Pluto and Senda…but I digress).

While we can’t find photons from a missing moon in our own backyard, the Chinese have discovered a Jupiter sized planet that is an ASTOUNDING 17,000 light years from Earth. That unnamed planet crossed in front of its parent star as viewed from Earth and caused it to get dimmer. Such an effect has been observed before with a planet around the star HD209458 that is “only” 150 light years away. The new Chinese discovery was made at MUCH greater distances due to an effect called gravitational lensing. At this rate, in a few years we’re going to know more about planets on the other side of the galaxy that we will about planets circling stars near our own Sun.

Meanwhile, the whole universe is getting dimmer as star formation slows. Even if light pollution is halted, in a few billion years there won’t be much to see anyway. Enjoy it while you can.

And “while you can” may be less time than you think if the most astounding article about dimness is true: The sun is getting visibly dimmer in just the past few decades!