Skip to main content

Thank you for visiting nature.com. You are using a browser version with limited support for CSS. To obtain the best experience, we recommend you use a more up to date browser (or turn off compatibility mode in Internet Explorer). In the meantime, to ensure continued support, we are displaying the site without styles and JavaScript.

Volume 475 Issue 7357, 28 July 2011

More than 200 years ago, mathematician Joseph-Louis Lagrange predicted the existence of what became known as Trojan asteroids  small bodies that can stably share the orbit of a planet if they remain near ‘triangular points 60° ahead of or behind it in its orbit. Jupiter has thousands of Trojans; Mars and Neptune have some too. Now Earth is shown to have a Trojan. A search of data collected by NASA’s Wide-field Infrared Survey Explorer (WISE) satellite revealed the asteroid 2010 TK7 as a strong candidate, and subsequent optical observations confirm its status as a Trojan companion of Earth, oscillating around the L4 (leading) Lagrange triangular point. The cover imagines 165 years of motion of 2010 TK7 seen from a vantage point outside of, and above, Earth’s orbit. Cover image: Paul Wiegert.

Volume 475 Issue 7357

Subscribe

Editorial

  • Regulators must look past visceral disgust about human–animal hybrids. Strict but sensible rules are needed for research on hybrid embryos and chimaeric animals that could produce therapies.

    Editorial

    Advertisement

  • The Heartland Institute's climate conference reveals the motives of global-warming sceptics.

    Editorial

  • Zoologists should follow botanists in allowing online-only announcements of new species.

    Editorial
Top of page ⤴

World View

  • Paul Knoepfler explains why he joined the ranks of the blogosphere, and why you should too.

    • Paul Knoepfler
    World View
Top of page ⤴

Research Highlights

Top of page ⤴

News

Top of page ⤴

Correction

Top of page ⤴

News Feature

Top of page ⤴

Comment

  • International agreements are not enough. Interlinked national and regional tools are also needed to reduce carbon emissions, say Mark Maslin and Joanne Scott.

    • Mark Maslin
    • Joanne Scott
    Comment
Top of page ⤴

Books & Arts

  • Andrew Robinson enjoys a history of a controversial probability tool — Bayes' theorem.

    • Andrew Robinson
    Books & Arts

  • Steven Campana enjoys a refreshing account of human pressure on the oceans' top predator.

    • Steven Campana
    Books & Arts

  • The Prinzhorn museum shows how psychiatric patients' works have inspired artists, finds Giovanni Frazzetto.

    • Giovanni Frazzetto
    Books & Arts
Top of page ⤴

Correction

Top of page ⤴

Correspondence

Top of page ⤴

News & Views

  • As sesquicentennial celebrations commemorate the discovery of Archaeopteryx as a historical symbol of evolution and the oldest fossil bird, new work shakes the dinosaur family tree — and our view of this icon. See Article p.465

    • Lawrence M. Witmer
    News & Views

  • Shining light on an antiproton masquerading as an electron in a helium atom is a rich source of physics. An approach that brings this technique to unprecedented precision will allow new tests of matter–antimatter symmetry. See Letter p.484

    • Mike Charlton
    News & Views

  • Dust and glowing hydrogen obscure the Carina complex at visible wavelengths. An X-ray study, combined with infrared surveys, provides knowledge of newly formed stellar associations and past supernova explosions in this system.

    • Theodore R. Gull
    News & Views

  • Magnesium binds to enzymes and nucleic acids and is essential for their activity. It emerges that this ion can also function as a signalling molecule with a crucial role in the immune system. See Article p.471

    • Ning Wu
    • André Veillette
    News & Views

  • Wave energy has long been proposed to be a source of the hot solar corona and fast solar wind. Direct measurements made by spacecraft have finally established that coronal waves are ubiquitous and can have the required energy. See Letter p.477

    • Peter Cargill
    • Ineke De Moortel
    News & Views
Top of page ⤴

Article

Top of page ⤴

Letter

Top of page ⤴

Corrigendum

Top of page ⤴

Feature

Top of page ⤴

Futures

  • Getting to grips with history.

    • Scott Akalis
    Futures
Top of page ⤴
Nature Briefing

Sign up for the Nature Briefing newsletter — what matters in science, free to your inbox daily.

Get the most important science stories of the day, free in your inbox. Sign up for Nature Briefing

Search

Advanced search

Quick links