On the Horizon: News from the Frontiers of Science

By Spotts, Peter N | The Christian Science Monitor, September 6, 2007 | Go to article overview

On the Horizon: News from the Frontiers of Science


Spotts, Peter N, The Christian Science Monitor


Astronomers solve asteroid mystery

Imagine reconstructing an entire game of billiards from the last few shots.

That's akin to the "what dunnit" US and Czech astronomers assigned themselves. They were looking for the source of a surge in "impactor" collisions with Earth and the moon that peaked about 100 million years ago. The events include impactors that did in the dinosaurs some 65 million years ago and carved the crater Tycho on the moon.

Over the years, some researchers have argued that comets were the source; others said it was asteroids. The culprit, according to the new research: an asteroid the team has dubbed Baptistina, after a group of asteroids between Mars and Jupiter. The group is clustered around Baptistina 298, an asteroid discovered in 1890, and the group shares its chemical characteristics.

Combining observations of the asteroid group's current behavior with computer simulations to, in effect, run the picture in reverse, the team came up with this scenario: Some 160 million years ago, the 105-mile-wide parent asteroid was whiling away the eons near the inner edge of the asteroid belt when it was smacked by another asteroid about one-third its size. Roughly 20 percent of the largest shards, ranging in size from about a half mile wide to six miles across, were drawn into orbits that cross Earth's path around the sun.

The good news: "We are in the tail end of this shower," says William Bottke, a scientist at the Southwest Research Institute in Boulder, Colo., and a member of the team reporting its results in Thursday's issue of the journal Nature.

Ancient orchid discovery

A bee cloaked in orchid pollen and encased in fossilized tree sap has become Exhibit A in the case for an ancient lineage for the showy plants.

Orchids' evolutionary history has long been contentious. Some scientists have argued for a relatively recent rise some 26 million years ago, based in large part on a dearth of fossil evidence. …

The rest of this article is only available to active members of Questia

Already a member? Log in now.

Notes for this article

Add a new note
If you are trying to select text to create highlights or citations, remember that you must now click or tap on the first word, and then click or tap on the last word.
One moment ...
Default project is now your active project.
Project items
Notes
Cite this article

Cited article

Style
Citations are available only to our active members.
Buy instant access to cite pages or passages in MLA 8, MLA 7, APA and Chicago citation styles.

(Einhorn, 1992, p. 25)

(Einhorn 25)

(Einhorn 25)

1. Lois J. Einhorn, Abraham Lincoln, the Orator: Penetrating the Lincoln Legend (Westport, CT: Greenwood Press, 1992), 25, http://www.questia.com/read/27419298.

Note: primary sources have slightly different requirements for citation. Please see these guidelines for more information.

Cited article

On the Horizon: News from the Frontiers of Science
Settings

Settings

Typeface
Text size Smaller Larger Reset View mode
Search within

Search within this article

Look up

Look up a word

  • Dictionary
  • Thesaurus
Please submit a word or phrase above.
Print this page

Print this page

Why can't I print more than one page at a time?

Help
Full screen
Items saved from this article
  • Highlights & Notes
  • Citations
Some of your highlights are legacy items.

Highlights saved before July 30, 2012 will not be displayed on their respective source pages.

You can easily re-create the highlights by opening the book page or article, selecting the text, and clicking “Highlight.”

matching results for page

    Questia reader help

    How to highlight and cite specific passages

    1. Click or tap the first word you want to select.
    2. Click or tap the last word you want to select, and you’ll see everything in between get selected.
    3. You’ll then get a menu of options like creating a highlight or a citation from that passage of text.

    OK, got it!

    Cited passage

    Style
    Citations are available only to our active members.
    Buy instant access to cite pages or passages in MLA 8, MLA 7, APA and Chicago citation styles.

    "Portraying himself as an honest, ordinary person helped Lincoln identify with his audiences." (Einhorn, 1992, p. 25).

    "Portraying himself as an honest, ordinary person helped Lincoln identify with his audiences." (Einhorn 25)

    "Portraying himself as an honest, ordinary person helped Lincoln identify with his audiences." (Einhorn 25)

    "Portraying himself as an honest, ordinary person helped Lincoln identify with his audiences."1

    1. Lois J. Einhorn, Abraham Lincoln, the Orator: Penetrating the Lincoln Legend (Westport, CT: Greenwood Press, 1992), 25, http://www.questia.com/read/27419298.

    Cited passage

    Thanks for trying Questia!

    Please continue trying out our research tools, but please note, full functionality is available only to our active members.

    Your work will be lost once you leave this Web page.

    Buy instant access to save your work.

    Already a member? Log in now.

    Search by... Author
    Show... All Results Primary Sources Peer-reviewed

    Oops!

    An unknown error has occurred. Please click the button below to reload the page. If the problem persists, please try again in a little while.