Solar System

Chandra Detects the First X-rays Coming From Our Kuiper Belt

Lisse and McNutt
Carey Lisse (left) and Ralph McNutt Jr. (right)

We are pleased to welcome a pair of distinguished guests to the Chandra blog. Carey Lisse is currently a principal staff scientist at Johns Hopkins University Applied Physics Laboratory (JHU-APL). He has used ACE, Chandra, EUVE, HST, ROSAT, Spitzer, and XMM-Newton as well as numerous ground based telescopes to study the physical properties of many Solar System objects. Ralph McNutt Jr. is a physicist also at JHU-APL. Among his many other positions, he serves as the co-investigator for the PEPSSI instrument aboard New Horizons. He also been the principal investigator on many other spacecraft and experiments designed to explore the Solar System and beyond. Lisse and McNutt are the 1st and 2nd authors of a paper that is the basis for our latest press release, about the surprising Chandra detection of Pluto.

Once the stuff of science fiction when we were kids, the fantastically successful NASA New Horizons mission's flyby of Pluto in July 2015 has transformed our understanding of Pluto from a point-like object into a fascinating world. It has also inspired a plethora of new observations of the system to take advantage of the once-in-a-lifetime flyby event. We ran one of these sets of observations using NASA's Chandra X-ray Observatory. Launched in 1999, Chandra is now one of the established premier observatories of our time - in fact it is one of NASA's four Great Observatories (along with the Hubble Space Telescope, Spitzer Space Telescope, and the Compton Gamma Ray Observatory ).

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X-ray Detection Sheds New Light on Pluto


The first detection of Pluto in X-rays has been made using NASA's Chandra X-ray Observatory in conjunction with observations from NASA's New Horizon spacecraft. As reported in our press release this result offers new insight into the environment surrounding the largest and best-known object in the solar system's outermost regions.

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Comets in the "X"-Treme


For millennia, people on Earth have watched comets in the sky. Many ancient cultures saw comets as the harbingers of doom, but today scientists know that comets are really frozen balls of dust, gas, and rock and may have been responsible for delivering water to planets like Earth billions of years ago.

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Jupiter: Solar Storms Ignite 'Northern Lights' on Jupiter


Solar storms are triggering X-ray auroras on Jupiter that are about eight times brighter than normal over a large area of the planet and hundreds of times more energetic than Earth's 'northern lights,' according to a new study using data from NASA's Chandra X-ray Observatory. This result is the first time that Jupiter's auroras have been studied in X-ray light when a giant solar storm arrived at the planet.

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Chandra Awaits Comet Siding Spring's Approach to Mars


On October 19th, Chandra will join with telescopes across the world, in orbit around Earth, and even on and around Mars, as Comet Siding Spring makes an extremely close approach to the Red Planet.

This is an extremely exciting event because scientists have determined this comet has been traveling for maybe a million years from the distant Oort Cloud. This will be the first time that humans have ever captured images of a comet from the Oort Cloud, which is an enormous reservoir of left over debris from the formation of the Solar System. (Previous observations and spacecraft visits of comets came from those that originated in the much closer Kuiper Belt.)

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Close Planetary Pair and Chandra


All this week, Venus and Jupiter have appeared very close to each other in the night sky. Most people in the Northern Hemisphere have been able to spot the planetary duo in the western skies about four hours after sunset.


Jupiter, Moon and Venus Behind the Trees. Image Credit: Marco T.

This close pairing is a nice treat for skywatchers on Earth, but it really is an optical illusion of sorts. The planets are, of course, nowhere near each other. Venus is about 75 million miles away in one direction and Jupiter is over 500 million miles away in the other. Venus and Jupiter simply appear to come close to another from our vantage point on Earth as they travel in their usual orbits around the Sun.

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Chandra and the Latest Giant Solar Flare


On Friday March 2, 2012, we noticed Sunspot Group 1429 moving onto the Earth facing part of the Sun. The NOAA space weather service informed us that the magnetic topology was complex and this was a cell to watch out for. Sure enough, on Sunday night (March 4, Eastern time) the Sun emitted a short X1 flare. We all felt a bit better, because this often will relax the magnetic field. And since it was well off on the Eastern limb of the Sun, any coronal mass ejection (CME) should have missed us.

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Maneuvering Chandra in the Solar Storm


By now you may have seen the headlines:

"Strongest Solar Storm Since 2005 Striking Earth."
"Raging Solar Storm Triggers Northern Lights"
"Solar Storm Is Taste of Things to Come."

Hopefully, for some of you it was a nice view of the northern lights. For us, it was a busy start to the week. This started last Thursday (Jan. 19, 2012) with an M2 solar flare. Flares below M5 usually don't worry us too much, but this one was unusually long - about 6 hours - which indicated a lot of material was involved and coronal mass ejection (CME) was heading our way with a scheduled arrival of Saturday or Sunday. Sure enough on Saturday (Jan. 21), the ACE satellite, the GOES satellites and our on-board monitors started to notice a minor jump in the background particles. The rate got even higher by Sunday. By Sunday night, we had received about half our orbital budget.

When this happened our alerts system went off and we had a phone meeting. This was around half time of the NFC Champion ship game, not that I knew, since I was with my daughters at a Girl Scout camp reunion. So while they were cooking s'mores in the snow, I was on my cell phone. We know that periodically long slow radiation storms will happen and we "budget" for 10 a year. This is the first storm like this in several years. So when we "met", we reviewed how much time was left in the orbit (5 hours) and what additional fraction of out budget we would receive in the next 5 hours assuming either constant or worst-case. Since it was only 5 hours until the end of the orbit, we figured the 50% of the budget might get to 55% so we decided to ride it out, go behind the Earth and start fresh on the next orbit. Little did we know, we'd never get there.

Northern lights
Northern lights dance over the Lyngan Alps in a picture taken Tuesday night near Tromsø, Norway.Photograph by Ole C. Salomonsen,
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Winter Solstice 2011


This year, the winter solstice takes place on Thursday, December 22 at 12:30 a.m. EST. Many people know that the winter solstice marks the day when winter officially stars in the Northern Hemisphere, and when days will start to become incrementally longer. But what exactly is going on?

It all has to do with the tilt of the Earth's axis. In other words, the Earth does not rotate on its axis straight up and down in relation to its path around the Sun. Rather, it is always angled at 23.5 degrees. So as the Earth travels around the Sun during the course of the year, one pole is tilted more toward the Sun that the other with the exception of two days: the vernal (spring) and autumnal (fall) equinoxes.

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A Solar Flare That Will Blow Your Socks Off


By now many of you who follow the Sun have probably heard about the “solar flare that will blow your socks off,” which occurred in early morning of Sunday June 7. Here at the Chandra X-ray Center we watched it too -- with some pride as our colleagues downstairs with the Solar Dynamics Observatory were responsible for some of the movies that were being circulated around the Internet. On the one hand, an M2 is a medium-sized event and not usually a big deal. On the other hand, I also thought of a slogan written on my whiteboard a few years ago, “West limb worry.”

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