Astronomy Now Home
Home Magazine Resources Store

On Sale Now!

The October 2014 issue of Astronomy Now is on sale! Order direct from our store (free 1st class post & to UK addresses). Astronomy Now is the only astronomy magazine specially designed to be read on tablets and phones. Download the app from Google Play Store or the Apple App Store.

Top Stories

Earthshine used to test life detection method
...By imagining the Earth as an exoplanet, scientists observing our planet's reflected light on the Moon with ESO's Very Large Telescope have demonstrated a way to detect life on other worlds...

Solid buckyballs discovered in space
...Astronomers using NASA’s Spitzer Space Telescope have detected a particular type of molecule, given the nickname “buckyball”, in a solid form for the first time...

Steamy water-world gets the Hubble treatment
...Hubble Space Telescope observations of a 7 Earth-mass planet find an unusual water-rich world swathed in a thick, steamy atmosphere...

IBEX reveals dynamic
Solar System edge

Posted: 01 October 2010

Bookmark and Share

A new set of all-sky maps from NASA’s Interstellar Boundary Explorer (IBEX) shows that conditions at the edge of our Solar System are more dynamic than first thought.

Click here for visualization to show the ribbon-like structure untangling over time. Image: IBEX Science Team/Goddard Scientific Visualization Studio/ESA.

IBEX monitors the conditions at the boundary between the local interstellar medium and the heliosphere – the protective bubble that shields and protects our Solar System. It measures energetic neutral atoms (ENAs) which are created in the interstellar boundary where solar wind particles collide with the interstellar medium. The ENAs race in towards the Sun at speeds ranging from 160,000 to over 3.5 million kilometres per hour.

The first data map released in October 2009 showed an unpredicted bright ribbon of energetic neutral atoms emanating towards the Sun from the edge of the Solar System. Now, a second set of maps based on another six-months of data collection, shows dramatic changes to that ribbon, which appears to have 'untied', although the large scale structure of the ribbon has remained stable.

Click here for a comparison of IBEX's first and second all-sky maps. Image: IBEX Science Team/Goddard Space Flight Center.

“What we’re seeing is the knot pull apart as it spreads across a region of the ribbon,” says David McComas, IBEX principal investigator and an assistant vice president at Southwest Research Institute in San Antonio. “To this day the science team can’t agree on exactly what causes the knot or the ribbon, but by comparing different sky maps we find the surprising result that the region is changing over relatively short time periods. Now we have to figure out why.”

The IBEX team think that the ribbon is somehow ordered by the direction of the local interstellar magnetic field outside the heliosphere, but that this is influencing the structure of the heliosphere more than previously believed. In the first data set, the 'knot' feature displayed the highest energies, whereas now it has faded by as much as a third, and has spread out – untied – to lower and higher latitudes.

“Our discovery of changes over six months in the IBEX ribbon and other neutral atoms propagating in from the edge of our Solar System show that the interaction of our Sun and the galaxy is amazingly dynamic,” says McComas. “These variations are taking place on remarkably short timescales.”

The Planets
From tiny Mercury to distant Neptune and Pluto, The Planets profiles each of the Solar System's members in depth, featuring the latest imagery from space missions. The tallest mountains, the deepest canyons, the strongest winds, raging atmospheric storms, terrain studded with craters and vast worlds of ice are just some of the sights you'll see on this 100-page tour of the planets.

Hubble Reborn
Hubble Reborn takes the reader on a journey through the Universe with spectacular full-colour pictures of galaxies, nebulae, planets and stars as seen through Hubble's eyes, along the way telling the dramatic story of the space telescope, including interviews with key scientists and astronauts.

3D Universe
Witness the most awesome sights of the Universe as they were meant to be seen in this 100-page extravaganza of planets, galaxies and star-scapes, all in 3D!


© 2014 Pole Star Publications Ltd.