Jupiter, the largest and heaviest planet in the solar system, teams up with the Moon the next few nights. Jupiter looks like a brilliant star. It’s well to the lower left of the Moon tonight, but will huddle quite close tomorrow night.

“Hot Jupiters” aren’t very friendly. Few of the giant planets have nearby companion planets. That could mean that the hot Jupiters have kicked other planets away.

Hot Jupiters were the first planets discovered in other star systems. They’re big, heavy balls of gas, like Jupiter, the giant of our own solar system. But while Jupiter is far from the Sun, hot Jupiters are quite close in, so they’re heated to hundreds or thousands of degrees.

Such planets can’t form that close to a star — it’s just too hot. They must have been born farther out, then moved inward. The question is whether that’s a gentle process, allowing the Jupiter to co-exist with other planets, or a more violent one that boots the other planets out of its way. And so far, the “violent” scenario has been the most likely, because astronomers have found few close companion planets.

But in a recent study, about one in eight hot Jupiters did have a nearby companion. Those Jupiter-like worlds must have migrated inward in the gentler process, sparing their sibling worlds. And warm Jupiters — those that are a little farther out — were more hospitable: about two-thirds had close companions. So there may be more than one way for a Jupiter to fall toward its parent star.

Our own Jupiter teams up with the Moon the next few nights. It looks like a brilliant star. It’s well to the lower left of the Moon tonight, but will huddle much closer tomorrow night.
 

Script by Damond Benningfield

The "hot Jupiter" planet Wasp 18 orbits its parent star in this artist's concept. Hot Jupiters are giant worlds similar to Jupiter, the largest planet in our own solar system, but much closer to their parent stars, so they are extremely hot. Such planets probably were born much farther out, then migrated inward to their current positions. [NASA/CXC/SAO/I.Pillitteri et al]

Lyra, the harp, is high overhead at nightfall. Its leading light, Vega, is one of the brighter stars in the night sky. In the 1800s, the government built observatories in the western U.S. to use Vega and other bright stars to establish the exact locations of cities and towns.

As the United States expanded westward in the late 1800s, it didn’t really know where everything was. The precise locations of towns and other landmarks were a little fuzzy, so maps could be off by quite a bit. To clear things up, the country turned to the stars. It dispatched surveying parties and established special observatories from Nebraska to Utah and Nevada. And one of those observatories took its first official look at the stars 150 years ago today.

The observatory was atop a hill near Ogden, Utah, a railroad junction with a population of about 2,000. The facility consisted of three rooms covered by a tin roof, including one room for recording the weather.

The observatory used a “transit” telescope to measure the positions of the stars. It then used telegraph signals to obtain the time from several cities whose exact positions were known. Comparing the star positions with the time allowed astronomers to accurately compute the location.

Ogden’s observatory operated through 1874, and took thousands of star sightings. In addition, several groups fanned out from Ogden to determine the positions of other locations.

The first stars observed from Ogden included several bright stars of Lyra, the harp, which is high overhead as night falls. Its leading light, Vega, is one of the brighter stars in all the night sky, so it’s easy to pick out — a bright light that helped illuminate the western United States.
 

Script by Damond Benningfield