Featured Research

from universities, journals, and other organizations

Astronomers Discover Apparent "Outer Edge" To The Solar System

Date:
October 30, 2000
Source:
University Of Arizona
Summary:
Our solar system may have an outer "edge" just outside the orbit of Pluto, astronomers announced recently. Their results suggest that early in the history of the solar system, some event stripped away most of the planet-building material beyond 50 times Earth's distrance from the sun.

Our solar system may have an outer "edge" just outside the orbit of Pluto, astronomers announced recently. Their results suggest that early in the history of the solar system, some event stripped away most of the planet-building material beyond 50 times Earth's distrance from the sun.

Lynne Allen and Gary Bernstein, of the University of Michigan, and Renu Malhotra of the University of Arizona Lunar and Planetary Laboratory presented the evidence October 24, 2000 at the Division of Planetary Sciences meeting in Pasadena.

It has long been thought that some comets must originate from a collection of small icy bodies orbiting beyond Neptune. These so-called "Kuiper Belt Objects" would be left over from the formation of the large planets 5 billion years ago. The Kuiper Belt Objects were purely hypothetical until 1992, when David Jewitt and Jane Luu of the University of Hawaii discovered the first one. Since that time, over 300 Kuiper Belt Objects have been discovered -but none of them are more than about 55 times as far from the sun as Earth, or 55 AU.

Astronomers talk about solar system distances in terms of "astronomical units." An astronomical unit, or one AU, is the distance from Earth to the sun. By comparison, Neptune is 30 AU from the sun, and Pluto ranges from between 30 to 50 AU.

Does the solar system really end beyond Pluto's orbit? Or are the more distant objects just too faint to have been found so far? To address this question, Allen, Bernstein, and Malhotra searched 6 patches of sky, each about the size of the full moon, using a state-of-the-art electronic camera at the Cerro Tololo Inter-American Observatory in the Chilean Andes.

Astronomers have discovered more than 300 Kuiper Belt Objects, but none of them are more than 55 times as far from the sun as Earth. Does the solar system really end beyond Pluto's orbit?

These observations, in 1998 and 1999, were sensitive enough to see a 160-kilometer (100-mile) Kuiper Belt Object to at least 65 AU. They discovered 24 new Kuiper Belt Objects, 9 of which are 160 kilometers or bigger, but again the most distant is near the outer limit of Pluto's orbit. This is the strongest evidence yet that more distant objects are missing.

Some of the known Kuiper Belt Objects as well as many comets are on trajectories that will carry them well beyond the orbit of Pluto. But these are all believed to have formed inside Pluto's orbit and then been pushed outward by an encounter with Neptune or another planet. There are still no known objects which appear to have been created outside Pluto's orbit.

So astronomers are left to wonder what explains this apparent edge: was the primordial solar system originally "small"? Or were there once more distant objects that were pulled away by the gravity of a passing star? Astronomers at telescopes around the world are currently conducting further surveys in an effort to learn more about the history of our solar system.

This Kuiper Belt survey was funded by grants from NASA and the National Science Foundation.

Images and text available at http://www.astro.lsa.umich/users/garyb/WWWKBO.


Story Source:

The above story is based on materials provided by University Of Arizona. Note: Materials may be edited for content and length.


Cite This Page:

University Of Arizona. "Astronomers Discover Apparent "Outer Edge" To The Solar System." ScienceDaily. ScienceDaily, 30 October 2000. <www.sciencedaily.com/releases/2000/10/001030082725.htm>.
University Of Arizona. (2000, October 30). Astronomers Discover Apparent "Outer Edge" To The Solar System. ScienceDaily. Retrieved September 1, 2014 from www.sciencedaily.com/releases/2000/10/001030082725.htm
University Of Arizona. "Astronomers Discover Apparent "Outer Edge" To The Solar System." ScienceDaily. www.sciencedaily.com/releases/2000/10/001030082725.htm (accessed September 1, 2014).

Share This




More Space & Time News

Monday, September 1, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Space Shuttle Discovery's Legacy, 30 Years Later

Space Shuttle Discovery's Legacy, 30 Years Later

Newsy (Aug. 30, 2014) The space shuttle Discovery launched for the very first time 30 years ago. Here's a look back at its legacy. Video provided by Newsy
Powered by NewsLook.com
Experiment Tests Whether Universe Is Actually A Hologram

Experiment Tests Whether Universe Is Actually A Hologram

Newsy (Aug. 27, 2014) Researchers at Fermilab are using a device called "The Holometer" to test whether our universe is actually a 2-D hologram that just seems 3-D. Video provided by Newsy
Powered by NewsLook.com
SpaceX’s Falcon 9 Rocket Explodes After Liftoff

SpaceX’s Falcon 9 Rocket Explodes After Liftoff

Newsy (Aug. 23, 2014) The private spaceflight company says it is preparing a thorough investigation into Friday's mishap. Video provided by Newsy
Powered by NewsLook.com
Did Russia Really Find Plankton On The ISS? NASA Not So Sure

Did Russia Really Find Plankton On The ISS? NASA Not So Sure

Newsy (Aug. 21, 2014) Russian cosmonauts say they've found evidence of sea plankton on the International Space Station's windows. NASA is a little more skeptical. Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins