The Stelliferous Era

The Stelliferous Era is the age of stars: the stretch of cosmic history in which most of the universe’s energy comes from nuclear fusion in stars. In the scheme of Fred Adams and Gregory Laughlin it spans cosmological decades 6 to 14, from about a million to about 100 trillion (10¹⁴) years after the Big Bang. We live near its start.

The name comes from the Latin for “star-bearing”, and Adams and Laughlin introduced it in their 1997 review “A dying universe”. It is the second of the five eras in our Deep Time explorer, and the one this site is named after.

How the Stelliferous Era began

The era begins when stars become possible. Adams and Laughlin set the start at η = 6 (a million years), just after the universe turned transparent about 380,000 years after the Big Bang, at the end of the Primordial Era. Before then, they note, stars could not form at all.

The first real stars came later. As of October 2026, the most distant spectroscopically confirmed galaxy is MoM-z14, at redshift 14.44, seen about 280 million years after the Big Bang; the earlier record holder, JADES-GS-z14-0, was already bright 300 million years in. Stars must have been forming before that.

Milestones of the age of stars

Event	When (after the Big Bang)	η
First possible stars	About 1 million years	6
Cosmic star formation peaks	About 3.5 billion years	9.5
Sun and Solar System form	About 9.2 billion years (4.567 billion years ago)	9.96
Today	13.787 billion years	10.14
Sun reaches the tip of its red giant phase	About 21 billion years (7.6 billion from now)	10.3
Galaxies run out of gas for new stars	1 to 10 trillion years	12 to 13
Smallest red dwarfs burn out	About 12 trillion years	13.1
End of normal star formation	About 100 trillion years	14

Sources: Adams and Laughlin (1997); Madau and Dickinson (2014) for the star formation peak; Schröder and Smith (2008) for the Sun; Adams, Laughlin and Graves (2004) for red dwarfs.

What powers the Stelliferous Era

Stars shine by fusing hydrogen into helium, a process worked out by Hans Bethe in 1939. They also forge heavier elements and scatter them when they die, as described in the B²FH paper of 1957. Every planet and every living thing is built from that material, so the Stelliferous Era is also the only era we know of in which chemistry-based life is possible.

Where are we in the Stelliferous Era?

Very early, in ordinary years. Today’s 13.8 billion years are 0.014% of 10¹⁴ years: if the era were a 100-year human life, the universe would be about five days old. On the logarithmic clock, we sit near the middle: η = 10.14 in a span from 6 to 14. Adams and Laughlin made both points in 1997. We work through the math in is the universe young?

Two facts pull in opposite directions. Galaxies form far fewer stars than at their peak about 10 billion years ago, so the era’s most productive phase is over. Yet red dwarfs, the most common stars, live for trillions of years, and Adams and Laughlin estimated that about 80% of all stars formed so far have barely begun to evolve.

How the Stelliferous Era ends

The age of stars ends because of two clocks that run out at about the same time:

1. The gas runs out. Each generation of stars locks gas into remnants. Even with recycling and infall, Adams and Laughlin estimated that galaxies exhaust their star-forming gas within about 1 to 10 trillion years.
2. The longest-lived stars die. A red dwarf of 0.08 solar masses burns for about 12 trillion years. Red dwarfs never become red giants: they slowly heat up into “blue dwarfs” and finally fade as helium white dwarfs.

By about 10¹⁴ years, Adams and Laughlin conclude, essentially all normal star formation will have stopped. A trickle continues: collisions between brown dwarfs, failed stars too small to fuse hydrogen, can occasionally merge them into a new low-mass star, the main source of new stars in the following era.

Local events will come much sooner. The Milky Way is almost certain to swallow the Large Magellanic Cloud within about 2 billion years, and it has about a 50% chance of merging with Andromeda within 10 billion years (Sawala et al. 2025). The Sun will become a red giant and a white dwarf, and a 2026 study suggests its uneven mass loss could break up the outer Solar System within a few billion years afterward.

What comes next

When the last red dwarfs fade, the universe enters the Degenerate Era, when white dwarfs, brown dwarfs and neutron stars hold most ordinary matter. For the whole story, from here to beyond 10¹⁰⁰ years, read our guide to the future of the universe.