English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Zendy Open

Presents the pdf analysis as premium feature

PDF Analysis

Insights

Presents the summarisation as premium feature

Summarisation

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the zaia usage as premium feature

ZAIA

Zendy Tools

Zendy Plus

Presents the access of premium content as premium feature

Premium Content

A mysterious increase of radiocarbon 14C ca. 775 AD in the Earth's atmospherehas been recently found by Miyake et al. (Nature, 486, 240, 2012). A possiblesource of this event has been discussed widely, the most likely being anextreme solar energetic particle event. A new exotic hypothesis has beenpresented recently by Liu et al. (Nature Sci. Rep., 4, 3728, 2014) who proposedthat the event was caused by a comet bringing additional 14C to Earth. Here wecalculated a realistic mass and size of such a comet to show that it would havebeen huge (~100 km across and 10^{14}-10^{15} ton of mass) and would haveproduced a disastrous impact on Earth. Such an impact could not remainunnoticed in the geological records and chronicles. The absence of an evidencefor such a dramatic event makes this hypothesis invalid.

A comet could not produce the carbon-14 spike in the 8th century