Tag Archives: Cosmology

safe operating space

Footprint Calculator

How much land area does it take to support your lifestyle? Take this quiz to find out your Ecological Footprint, discover your biggest areas of resource consumption, and learn what you can do to tread more lightly on the earth.

There are limits to the individual’s ability to instigate major change on the Earth’s changing conditions. Many people indicated that, even after dramatically changing certain behaviors such as fuel usage, their scores were marginally changed (if at all) – and depending on which country you reside in, a certain allotment of environmental impact is prescribed via goods and services. Therefore, to reduce this allotment, collective action (through aggressive campaigning or swift policy changes) must take priority.

Of course, this is not to say that individual actions do not matter – indeed, collectivity is comprised of a large group of individuals. By committing to invest in solar rather than non-renewable energy sources or eliminating meat from your diet to reduce the amount of grains that must be grown to feed those animals or reducing time in the shower, you are advocating for the Earth and setting an example that others can follow.

At the rate things are going, the Earth in the coming decades could cease to be a “safe operating space” for human beings. That is the conclusion of a new paper published Thursday in the journal Science by 18 researchers trying to gauge the breaking points in the natural world.

Nine planetary boundaries
1. Climate change
2. Change in biosphere integrity (biodiversity loss and species extinction)
3. Stratospheric ozone depletion
4. Ocean acidification
5. Biogeochemical flows (phosphorus and nitrogen cycles)
6. Land-system change (for example deforestation)
7. Freshwater use
8. Atmospheric aerosol loading (microscopic particles in the atmosphere that affect climate and living organisms)
9. Introduction of novel entities (e.g. organic pollutants, radioactive materials, nanomaterials, and micro-plastics).

Prepared by researchers at the Stockholm Resilience Centre, the study looks specifically at how “four of nine planetary boundaries have now been crossed as a result of human activity.” Published in the journalScience* on Thursday, the 18 researchers involved with compiling evidence for the report—titled ‘Planetary Boundaries 2.0‘—found that when it comes to climate change, species extinction and biodiversity loss, deforestation and other land-system changes, and altered biogeochemical cycles (such as changes to how key organic compounds like phosphorus and nitrogen are operating in the environment), the degradation that has already take place is driving the Earth System, as a whole, into a new state of imbalance.

The conclusion that the world’s dominant economic model—a globalized form of neoliberal capitalism, largely based on international trade and fueled by extracting and consuming natural resources—is the driving force behind planetary destruction will not come as a shock, but the model’s detailed description of how this has worked since the middle of the 20th century makes a more substantial case than many previous attempts.

“When we first aggregated these datasets, we expected to see major changes but what surprised us was the timing. Almost all graphs show the same pattern. The most dramatic shifts have occurred since 1950. We can say that around 1950 was the start of the Great Acceleration,” says Steffen. “After 1950 we can see that major Earth System changes became directly linked to changes largely related to the global economic system. This is a new phenomenon and indicates that humanity has a new responsibility at a global level for the planet.”


quantum gravity

Axion monodromy inflation

Let us assume that the BICEP2 result is confirmed as cosmological, and indicates primordial gravitational waves generated during inflation. Within the context of inflationary theory, this groundbreaking discovery has important implications for quantum gravity, for which string theory is our leading candidate.

String theory contains a rather simple mathematical structure – monodromy – which naturally generates a significant tensor signal. In this guest post, I’ll describe that mechanism, and discuss its range of applicability as we currently understand it. (String theory also contains multiple axion fields, which in itself gives an interesting realization of assisted inflation, N-flation, covered nicely in an earlier blog post. It was later realized that along each such direction the monodromy effect operates; in general, one may consider a combination of these two mechanisms.)

Stable Orbits

Published on May 3, 2012

If gravity is so attractive, why doesn’t the earth just crash into the sun? Or the moon into the earth?

The answer: Stable Orbits

hyperbolic funnel video: http://bit.ly/r5xhng

minutephysics is now on Google+ – http://bit.ly/qzEwc6
And facebook – http://facebook.com/minutephysics
And twitter – @minutephysics

Minute Physics provides an energetic and entertaining view of old and new problems in physics — all in a minute!

How to Simulate the Universe on your Laptop

Published on Sep 1, 2012

AfterEffects Tutorial on how to Simulate the Universe: http://dft.ba/-3v1X
Millennium Simulation – http://dft.ba/-3v12
Also, explore a map of the big bang! http://www.bigbangregistry.com

MinutePhysics is on Google+ – http://bit.ly/qzEwc6
And facebook – http://facebook.com/minutephysics
And twitter – @minutephysics

Minute Physics provides an energetic and entertaining view of old and new problems in physics — all in a minute!

Music by Jake Chudnow

Thanks to Nima Doroud for contributions and to Perimeter Institute for support.