Twilight Moon, Busy Sun And Hubble Finds Most Ancient Galaxy

The lunar crescent joins holiday lights atop one of Duluth’s downtown skywalks this week. Photo: Bob King

Oh, poor astronomer that I am! I stayed up too late observing with telescope and binoculars through breaks in the clouds and missed the Leonids this morning. Forgive me, I needed to sleep. Good thing Tuesday morning they’re predicted to max out again (10-15 per hour). Did you get to see them?

Jim Schaff of Duluth nabbed a single shower member and a handful of random or sporadic meteors. Note that the Taurids and the occasional fireballs they pitch are still active. I saw two nice 1st magnitude ones last night.

With the recent total eclipse, auroras and meteor showers in the news, I nearly forgot about the return of the crescent moon. A couple nights ago its sharp form cut a white arc in the blue twilight sky above the city’s Christmas decorations. Tonight a fatter version of the moon will shine high in the southwest before nightfall.

Consider taking your own pictures of the crescent at twilight with camera or cellphone. It’s not difficult. Find a scene with either an interesting silhouette or something lit up like a roadway or your neighbor’s holiday lighting and include it in the foreground. Typical exposures are short enough at dusk to hand-hold a cellphone without the worries of shake and blur.

Sunspot counts have been higher this week than anytime since November 2011. While no spot or group is especially large, more activity improves chances for future northern lights displays. Photo taken at 9 a.m. CST this morning by the orbiting SOHO observatory. Credit: NASA/ESA

Although the sun shouts sunspot groups at the moment, only one of them  – Region 1614 – has the potential to kick out a moderate-strength flare. However, a recent blast of solar wind will tickle the planet’s magnetic field over the next three days (Nov. 17-20) potentially firing up minor auroras across the northern U.S. and southern Canada.

We see the galaxy MACS0647-JD (inset) only 420 million years after the start of the birth of the universe in the Big Bang. Astronomers used the massive galaxy cluster MACS J0647.7+7015 (yellow fuzzies) as a gravitational zoom lens to spot it. Credit: NASA, ESA, and M. Postman and D. Coe (Space Telescope Science Institute), and the CLASH team

This week the Hubble Space Telescope pushed our vision further back to the beginning of time and space when astronomers uncovered the most distant galaxy yet. Named MACS0647-JD, its light has traveled 13.3 billion years to reach Earth. We shouldn’t be seeing it at all – it’s too faint and incredibly red, a consequence of its light having been stretched from shorter, bluer wavelengths to longer, redder ones as a result of the expansion of the universe. Astronomers say the galaxy’s light has been redshifted.

Lucky for us, “8 billion years into its journey, the galaxy’s light took a detour along multiple paths around the massive galaxy cluster MACS J0647.7+7015,” according to a recent European Space Agency press release. “The cluster’s gravity boosted the light from the faraway galaxy, making the images appear far brighter than they otherwise would.”

In this illustration, the gravity of a large galaxy cluster not only bends the light of a much more distant galaxy but focuses and brightens it into multiple images. Credit: NASA/ESA/L. Calcada

The boost came courtesy of gravitational lensing. As I described in a recent blog on the Hyades star cluster, massive objects warp the fabric space and cause light to be deflected from its original path. The gravity of a large galaxy cluster is so strong, it not only bends, brightens and distorts the light of distant galaxies behind it.but creates multiple images of the object. The investigating team found three magnified images of MACS0647-JD along the outskirts of the cluster.

What’s really cool about the new discovery is how small this thing is. Less than 600 light years across, this pipsqueak galaxy is 0.4% the size of the Milky Way, which measures some 150,000 light years across. We’re probably seeing the early stages of galaxy formation when smaller protogalaxies collided or were gravitationally drawn together to create the more familiar spirals and ovals of the present era.

Looking deep into space we see far back in time. I’ve always had fun imagining how might we dip into Earth’s past to see the dinosaurs roaming again from a galaxy 70 million or more light years away. Of course, we’d need a telescope powerful enough to see right down to the planet’s surface. While that will never happen, it does makes for nice daydream.

1 Response

Comments are closed.